Dave- i don't mean to second guess, especially after you have this all together. But, why use the aluminum plate again? Wouldn't stainless be better so it wouldn't corrode. Seems a 1/8" would be plenty. you could get them laser cut at a local shop and they would probably even do the countersinks for you it you wanted. Or you could fab yourself.
Second, instead of drilling different size holes, use a piece of stainless tubing that would make the outer dia of the bolt and t-nut the same. After you overdrill, fill and then drill to size, It's all going to be in a cylinder of epoxy anyway, right? so, it will be bearing against the hole all the way through, not just the skin.
just wondering if these ideas are viable.
joe
