Wooden tank, bulkhead fittings ???

I personally have not, but you may be able to find useful info (and tank plans) at www.garf.org.

The compression of the gasket itself should seal the fitting. You could supplement with a bead of silicone when tight. Never actually done it on wood though.

Assuming the wood will be treated with a resin to seal it? If so, apply the resin to the inside of the hole, and then use the bulkhead--it will seal and hold. Of course--building a tank can be a lot more costly than purchasing one unless you are going with something custm shaped or much larger than commonly available. Not a matter of if it can be done, of course it can, just a matter of why. I'd rather go with a standard tank and spend more on lights/fish/filtration. JMO

I am still finishing up building my custom wood tank setup. I bought the bulkhead/strainer combos from Foster+Smith (www.fostersmith.com), and I have been testing my tank seal for about 3 days now....everything is going great! No leaks! My tank is approx 150 gals, 5'x2'x2', and has an artificial rock back ans side walls which will conceal almost all filtration tubes. The bulkheads come with a rubber gasket on them and this is all that is needed. I have read articles of people using silicone smeared on the gasket for a better bond, only to have it fail later, making the gasket brittle and crumbly. Also, you cannot re-use a gasket coated with silicone because it will harden to the previous shape, and be useless for forming water-tight seals the second time (even breaking and cracking). As long as you have a smooth epoxy sealed tank interior (wouldn't hurt to seal the inside of hole either), the gasket should do it's job.