>I was wondering if the angle of a KTBH really reduces brace comb.
Not at all.
> I was also wondering if anyone had a prefered depth and/or length for their TBHs.
With square sides, 19" bars (the size of a langstroth) and 10 1/8" depth (9 5/8" + 3/4" is the same as a Langsroth deep on a 3/4" bottom board) the combs all collapses on me. Like a row of dominoes. ALL the combs collapsed. With 10 1/8" depth 15" bars and sloped sides I've only ever had one comb collapse.
With square sides, 19" bars and 7 1/2" depth, I've had the same luck as the KTBH. Less depth seemed to prevent the comb collapse problems. You still have to be careful, of course, but they don't go down like a row of dominoes.
Pcitures of both of mine are here:www.bushfarms.com