KR, I've been running solids for years. I never could get hydraulics to work.
On the A grind, I bought one for my first pan, a 49 pretty much stock engine, and it ran great. SU carb on that one. Then the '62, same, ran great, that bike with 8.5:1 pistons, and the cam as a rigid bobber, would do 125. Must have been a Wednesday bike. The '65 got stroked right away, 8.5's. A grind, auto advance, and was a pig to start, as I mentioned. Chucked the auto advance, clapped out, finally switched the cam to the B, and it was transformed. With the stocker 74 flywheels, the A grind was great. Really liked it. The B comes on a little higher in the rev range, as you would expect with more overlap.
Yes, I'm using the 38 VM on the 84" pan, seems to work o.k., a little rich off idle, other wise, it's fine through the rev range. I'm temped to work on that, drop the idle jet down a size, and then see if a different cutaway on the slide is needed to smooth up off idle. It may just be the overlap and I'm stuck with it. We'll see,