Yeah, I've never asked why he doesn't want to use the fir but I suspect its the same reason i would never do a boat interior for myself in teak, familiarity, it is so common that im so over the teak cave, it looks cheap to me,(even though its not) and of course dark. The washboarding problem is of course also one of the reasons why i have replaced quite a few teak decks over the years, what i referred to earlier as maintaining them to death. My last teak deck job was on a Cherubini 44, the decks had started out at about 1/2" teak, glued and screwed down to the 3/4" plywood sub deck with epoxy using a rabetted edge for the caulk seam so in effect you really only have to wear, scrub,sand it away less than 1/4" before the plugs and caulk are falling out and allowing moisture down into the sub deck which is exactly what happened (needless to say it was a ***** to remove.) If any of these junglewoods were useable ie, didn't check you would want to go thinner due to the weight and use full depth seams and no fasteners but the benefit is they are so hard you could probably pressure it. Im not so sure how well the caulk would adhere though. A friend did a very small ipe sole on his center cockpit Dawson 26 a few years back under my direction and it worked out well with the exception of some checking. We cut a piece of particle board to the shape we wanted, laid up a few layers of 1708 with polyester resin and then glued up the ipe about 3/16" thick with no fasteners and payed the seams with epoxy/graphite. My son then took it to work and put it through the wide belt sander, then flipped it and sanded off the particle board to the glass, it was then glued down to become the new top skin after recoring the sole so he got a sexy looking sole and didn't need to do any cosmetic repair after the recoring. Its been about 5 years now and the only issue has been the wood checking.
Steve.