I just got to ride with the New Steahly 12oz flywheel weight, HUGE difference, Bike even seems more powerful, much more luggable., Never stalled it not one time. Power is smoother and feels alot broader, although I know its not. Its worth the expense. I don't see that it will hurt riding on a MX track either.
It feels like more like a WR with a tad taller gearing and no gap between 3 & 4.

js

I have the 14oz but i am sure the 12oz is not much different. Stalls much less often with the flywheel. Well worth the expense.

I have a 50 tooth but I will replace it with a 48 when it is worn. The 50 makes the tire break loose faster than the 48. I ride in slippery mud and rocks in 1st and 2nd gear most of the time. I think a 49 would be fine. If you are riding in 3rd or higher maybe a 48 would suit you better.

I love crashing!