Thanks Tropico
I know the floor isn't exactly historically correct, although it is possibly closer than just a flat floor.
However, the complexity of what I see when I look at it is such that it looks like it must have been done that way on purpose, so I think it would pass casual observation by someone who hasn't a clue what he is looking at as being a historically correct design I am sure
The rear "floor" is at 5 degrees. The quoin I will have to doublecheck ... I am thinking something like 20 degrees, but I need to make sure before I commit to remembering that right. The quoin is still a little "slippery" under the pressure of the barrel. The still drying linseed oil may be part of that slipery equation. Maybe a few more floor degrees would have been better. Still, I am sure it is better than flat. If it was flat the quion would be shooing out like a greased pig.
When cutting the 5 degree angle on my compound miter saw, it was hard to keep both sides perfectly exact. I realized that being able to dial in "degrees" on a modern saw has it's drawbacks. I think the tolerance stackup is worse that just marking rise and run and cutting along the dotted line.
When I make the big carriage, too big for the compound miter saw, I will just mark rise/run in inches on the wood and rough cut with a skill saw, followed by chiseling the mortise finished. A table saw would be nice, but don't have one, and don't have the room for one.
I am thinking that measuring rise/run may be more accurate that dialing in an angle, measuring and starting at the correct starting point, and then reversing the angle for the other side to do it a second time over there.