OK- - - -it looks like you've got the torque problem addressed, if not completely solved. Do you plan to do any dyno work before you assemble things? I'd be looking for a very flat torque curve, one that will avoid having to downshift frequently. With a Brownie and a 2-speed axle, you'll have a good variety of ratios to choose from, and probably even a few selections that won't be needed if you make good choices of camshaft and ignition timing.
Do you have a crankshaft grinder yet? I might be able to help out on that subject, but that conversation would be better by PM.
Jerry