Ron, I think there are some gaps in the proposed rule changes.
In Lou's 2610 proposal, they could be flying at 75 mph.
And in Your open B speed reduction idea, some guys would run 9x5's @ 17K rpms's and fly @ 80 mph. C/F, Jimbo and others with Jetts don't like running them at those slow rpms. It's out of their power band. But at 18.5 or 19K with a 3" pitch the best speed anyone can get is 54 mph. And the hot engines are still in their sweet zone for rpms. My best engines will turn an APC 10x3 at 16.2k, so guys with hot engines will out pace me by 7 to 8 mph. I can live with that. It's better than the almost 24 mph difference that can occur now.

So I think a 3" max pitch on the prop with rpms in hte 18.5K range is the best way to go.

I will have to check with my local scale purists to see how they feel about the 50" - 55"rule. I don't particularly care about that part of the rule change.