In AMA, I used a .65 in "C" speed in the late '60's, but sometime later it was changed to "D" with same engine size. Never really understood why, but I wasn't flying speed anymore, so didn't pay much attention. There was some thought that Juniors couldn't hold onto a .65 going 200 mph, so I suppose that was it. I'm not sure if they made "Junior C" for .40's, but probably. I don't think we ever used less than .65 maximum in our biggest class, so no 10cc. If my math doesn't fail me, .65's would be 10.8cc? Maybe this was a return to the early '50's classes, but there wasn't anything between B and D until recently, when the NW rules for C speed was promoted and accepted for .40's. This is a cool event, IMO, with mini-pipes and either monoline or 2-line. The real problem with all the .29> speed event is that there are no suitable racing engines made anymore, or at least not easily available, like in the '60's.
I always used "lift-off" dollies, 3 wheelers, of my own design. They evolved a bit, and worked quite well. I did make one "pin dolly", and it also worked ok, but I didn't really like it. I made them track straight or slightly out, but I feel the real trick was to set the model on the dolly and drag it sideways (on asphalt or concrete) with a short piece of line. If this pull makes it yaw in, it's gonna be exciting at best. If it yaws, shorten the rear or change the wheel/tire so that it will slide...or move the front wheels forward. Like everything else, it's the CG that is your reference point. Anyway, it worked for me, back in the dim and distant past. I never read or heard of anybody else doing this, but did see some tires wrapped with vinyl electrical tape to make them slide sideways more easily. Often inside front, but also rear. Too much rear traction was really dangerous, hence the short rear and small tire.
Steve