Hey Andy,
Yeah, mine measure the same.
I'm guessing it's from hand drawing.
I'm also guessing it's why part "V" wasn't the "right" # of degrees in the template. (I made a bunch until I came up with one to match the template; I don't remember what it came out to).
I measured the 'print, and found the sides different, and figured it wasn't supposed to be
exact, but more of a guide to follow.
So I decided to go with the numbers in the white papers.
Just divided the angles out, (don't remember off the top of my head what they were either, but they where where the saw had detents, not between half degrees), and cut the top & bottom plates to just under 24". (I made mine out of baltic birch, and left enough thickness to veneer them). (Still haven't)
On the internal holes--
I cut mine out, and drilled and installed inserts for the smaller drivers in case I wanted to install them later.
I talked to Steve about it though, and he said that configuration was just for outdoor use.
They are room sensitive.
Enough I don't even want to write anything about them yet.
I had them in (just over) 13 x 11 x 9 room with an alcove, built to the same dimensions as Steve's reference room, and was expecting great things.
I'll just say I learned a lot about the importance of room treatment.
After trying my HDTs, and a pair of ML TLs, and both also sounding bad in this room with "great" proportions, it's time to build traps & diffusers before I say anything more.
Robert