• Bouyancy: Dave discussed how you do it in the water...but are there some suspect spots to look at now? What gasket around hatch cover do you usually use, one from a local hardware?  Should we reseat fittings. With silicone? or other filler? Would it be prudent to force air into the tanks and see where the most sudsy bubbling occurs?
• Re. fillers to use on hull....any suggestions. (Pedits?)
• Re. mast: things to look for (meat hooks on shrouds, etc). Or wait untill test rake if need to replace shrouds? Spinnaker lines and halyards not running smoothly. (Maybe try to refeed with tracer line?  lubricate fittings? In the mast track ...silicone spray?)

I am sitting on a vehicle heading to a tunnel project site near the Swiss border, so will use my Blackberry to put a few points down for you. It is not easy to type long answers on this keyboard but I will do my best.

MAST
1. Look carefully at the sheaves top and bottom. These are usually worn, sometimes very badly. Will damage halyard and/or be hard to turn. Use silicone lubricant. Some sheaves may be nylon - okay with rope halyard but not for wire. Replace if necessary.
2. Inspect entire wire halyard for damage. Should run freely, lay straight (if it wants to curl up, this is a sign of internal damage) and be "clean" of dirt, corrosion, etc. Look at the loops on each end to ensure they are okay, including the swaged sleeve. Make sure the rope connection is not frayed at the wire loop.
3. Inspect shrouds and look carefully at the turnbuckles, if so equipped. If they show signs of having been bent or damaged, replace and do not reuse.
4. Inspect all three halyards end to end for signs of damage. If all three run in the mast groove and are not running internally, make sure the loops at the end of the wire halyards are neat and small. If not, things will bind as you raise/lower sails. Using 1/8" or 3/16" lines help alleviate the problem (assuming wire halyards). If halyards are rope only, there should be no issue with 1/4" line as long as it has a smooth outer jacket.
5. While you are at it, check the wind indicator and mounting.
6. What is the condition of the mast pin?  What size is it? When mast is erected, weight of mast (and therefore rig tension) should not be on the pin. The pin should be loose when the mast is erected and shrouds attached. (Al's note: We just discussed this at Saturday's Round Table at the MSC: To take weight off the mast pin, you may need to add plastic (nylon??) of the type used for kitchen cutting boards at the foot of the mast step until the mast sits high enough to take weight off the pin. This may in turn require a rake re-check?)
7. Is there a rig tensioner (which there should be)?  Inspect, lubricate, test.
8. The spreaders are of concern on older rigs. They are loose and sloppy compared to the fixed and quite rigid ones on modern rigs. I upgraded both my W's. Check the bolts and fittings to make sure they are not sloppy. Check the distance between shrouds at the spreaders as well as the "attitude" of the spreaders - they should go up slightly toward spreaders (Al's note: shrouds??) when mast is erected. The spreader bracket can sometimes be bent or can be loose and this affects spreader positioning.

HULL (bottom)
Turn the boat over for inspection.
1. Look all around the edges where the joint between the hull and the topside is made. In the W's BSSC has, this may be the major source of leakage into forward and rear bounancy tanks (it was on my W2178). The gaps are not obvious unless the W is upside down. Caulking can provide a temporary fix, but thickened epoxy is better.
2. What does the c/b slot look like?  Cracks, chips existing?  This is a good time to remove and refinish the c/b. Check the angle of the c/b in full down position.  (Al's note: board should be able to go down to near the 83° max. allowed by the Class Rules)
3. Check the keel bands and make sure all screws are there and are tight. May want to remove screws and reinstall, sealing with epoxy as you do so. Now is the time to install slot gaskets if you are so inclined.
4. Check pintle/gudgeon mountings on transom as well as the drain plugs. All should be sealed and tight. Pintle/gudgeons should be thru bolted and caulked on the inside, too.
5. Check condition of rub rail. Poor condition here can lead to leaks in buoyancy compartments through loose screws or rivets.
6. Repair any serious scratches or damage to gel coat.

HULL (topside)
1. As you already have pointed out, check the gaskets. Everything you need to fix them is available at Canadian Tire. Use dense, closed cell foam tape.
2. Make sure the hatch cover retainers can clamp the hatch lids tightly. Note that these bolts are another source of leakage into the front/rear compartments.
3. Check and lubricate all cleats and blocks. Use through bolting on all cleats, if possible. Check screws and bolts to ensure they are tight.
4. Check the bow plate. This is almost always loose on older Ws that haven't had good attention. This is a critical area as it absorbs 100% of the forward rig (jib luff) tension.  You may need a small, strong person to go inside front compartment to get at bolts (and it should be thru bolted, not just screwed down - danger!). I have been able to get into the forward compartment when the W has been upside down but not when upright. 
5. Check for cracks along inside of fore/aft compartment bulkheads where they meet both the floor and the top deck. Make sure all screws and fittings are sealed and tightly installed. Check drain plugs and replace if necessary. 
6. General inspection of hiking straps, floor board, seats, bailers and other cockpit items. Good time to clean out last year's dirt and grime.   :-)
7. Check the bridle or traveller. I remember the traveler was a problem on one of those boats last year.
8. Check foredeck for cracks (usually caused by people walking on the old deck - to be discouraged).
9. Check mast step and pulpit for damage or wear. 
10. Check where the c/b box joins the thwart. On some older GRP boats this was a real point of weakness. May need strengthening here as it has to be solid to counter the stress of the c/b and help stiffen the hull.
11. Floorboard supports are often also the stiffeners for the bottom of the boat. These can break loose from the bottom over time; hull loses stiffness. Epoxy repairs required. Be careful, if installing new fasteners to secure the floorboards, that the bouancy compartment is not compromised (as happened on the W Mk2 "Mystic" under the mast step).

RUDDER
1. Check blade condition, repair. Will it meet measurement requirements?
2. Make sure of tight fit of tiller to rudder head.
3. Check and lubricate tiller extension. Is it firmly attached to the tiller? 
4. Check that the rudder holddown works, can be loosened quickly but will keep the rudder down when you need it down.

That is all I can think of for now. I have Blackberry writer's cramp so I will concentrate on the Austrian scenery going by. As for the actual bouancy testing, that is the last thing to worry about until the rest of the checks are done and required work completed.

Have fun!

Dave