Aw, nuts...

What's wrong with this picture?

AC 43.13 B states that a bolt must have at least one thread past the end of the nut. If I had a set of blueprints that stated what bolts I needed, this wouldn't be an issue. On the other hand, since I don't, this means that my method of choosing hardware is to find something for the correct size hole, cross-reference with the old hardware, and get what looks like the correct length. Unfortunately, any time you put a fitting on wood, especially when other fittings fit on top of that fitting, and not all fittings are the same thickness... you get the goldilocks method of finding the right bolt length.

Well, why don't you just choose bolts that are too long and that way you have enough? Because it doesn't work like that - there's usually a fixed length of thread, and then a thicker shaft on each bolt. The longer the bolt, the longer the shaft, not the threaded section. If the shaft protrudes past the fittings, the nut will only tighten to the shaft, leaving the fittings wobbly-loose and the bolt freely rotating in the hole. Bad idea. So, time to do the boltey-pokey. We put the short bolt in, we take the short bolt out, we put the too long bolt in, and we wrench it all out. We put the slightly longer bolt in, we take the slightly longer bolt out....