Looks great Storydude!
Have you considered using a carb from a .21 two-stroke?

I just got a little more runtime with my project last weekend. Unfortunately the weather is beginning to be so bad here in Denmark, that i'm not going to get much more runtime this year.
But I tried to change my clutch bell from 22 tooth to a 20 tooth, which was a big improvement! Better acceleration, lower temps and still ok topspeed. I'm still running the standard 48 tooth spur on my Hong Nor/Jammin' X2 CRT truggy, but I also have a 44 tooth spur from the X2 CR buggy. I'll try that later on, so I maybe can run a smaller clutch bell and also can mount the engine closer to the centerline.
I also have some plans to get more revs out of the engine (improving the flow through the intake manifold and mounting a fuel pressure regulator).
A friend of mine ran his Hobao Hyper 7 buggy with a 3 port .21 engine and as my 4 stroke truggy began reaching the optimum workingtemp I began to outrace him on topspeed! He was quite impressed and began to "feel the pressure" from the 4 stroke power!