Well I returned home to find this from Steve Brooks.  I'll be anxious to see how it shoots at various distances in November when gun, molds and casting equipment are all in one place.

Thanks Hiwall... be sure to look this up and post feedback.

Glenn,  the sample that Steve sent with the mold weighs in at 277.5gr.   His note said it was cast with 30:1.  I am going to try 20:1 and then 16:1.   

The bullet that Steve Baldwin showed me was about 280 but he has a much heavier version enabled by the faster twist like you are considering.   I'm thinking his heavier bullet was somewhere between 360 and 380gr and was seated waaayy out.   Of course my twist wouldn't support it and I'm anxious to demonstrate that my twist will support what I do have.   I won't be using mine for anything but some fun gong shooting.  And being a lighter Ballard that's ok by me.  Either way, I won't know till after November when I have the 35-40 back down here in Oklahoma.

Ran the calc's on the two reamers that John has info for. With the 3-degree leade angle there would be 0.229" of freebore (very nice IMHO) and with the 4-degree leade angle, that would result in 0.179" of freebore. Think longer is better. Slower transition into the rifling should be a plus as well as allowing for a longer bullet to spaced-out further, increasing powder capacity (for us BP shooters).