Thanks for the kind words. My opinion about angle although concrete is this, no matter what angle you choose, the bees will attach any new combs they build. The difference is I think that once the comb has hardened some, the angle becomes important to deter future attachment of the same comb. If the comb bears too much weight at the top, the bees will NEED to attach it at the sides and or bottom to keep it from collapsing. My hives are between 30-35 bars in length depending on which bars I am using and how many of each. My brood nest topbars are 1.25 inches and my honey bars are 1.5 inches. I use a router to cut a chamfer out of the center of the topbar now instead of ripping the angles and cutting toes into the ends. Its a lot easier and it adds just a touch more volume to the hive without having to change dimensions. My hives don't require legs to remain supported, the back end and the front end are rectangular cut and so they can provide lateral support in case of high winds and such. The legs were mostly to bring the hives to waist height for ease of working.
I still think a 15 degree angle cut out of the topbars for center guide is best from an attachment point of view, but in practice I believe it is too flat to provide much "guidance". Further a 45 degree angle chamfer bit for the router is a lot cheaper than a necessarily custom made, or machine shop purveyor supplied tool. I don't think its ideal, but it prevents a lot of work when it combs to training the bees to build straight comb.
As you say the bees are adaptable, the question is will the adaption make life easier or harder for you.
Scot Mc Pherson<br />McPherson Family Honey Farms<br />Davenport, IA<br />BeeWiki: <a href=\"http://beewiki.linuxfromscratch.org\" target=\"_blank\">http://beewiki.linuxfromscratch.org</a> <br /><br />Pics:<br /> <a href=\"http://linuxfromscratch.org/~scot/pics/bees/\" target=\"_blank\">http://linuxfromscratch.org/~scot/pics/bees/</a>