This is my setup which I feel is good enough to finally give out the helix I am messing with. The RPM seems to be consistent and hold well enough over a big temperature swing to say that it "should" work for most guys who want to run a softer aftermarket belt.
***Disclaimer***
I have NOT tested this on anything but a 146" Assault with 1.5" track at or around 1100' elevation is where our place is.
If you choose to buy the parts I am running I suggest you have a good idea of clutching and how to tune it incase your riding area is different, or conditions are different from where I have tested.
Primary clutch
Speedwerx H5 155-300 spring
Stock weights (Seems to have a lot better grip down low than Dalton)
Secondary clutch
Dalton White
Dalton Helix - 58/42-40 .40
The combination I would NOT recommend on the stock belt at all, it is made to work around the softer stickier belts. I could not make the OEM helix rev out quick enough on the softer belts even with really stiff springs. I had a 320 finish primary spring in my sled and it still wouldn't rip the rpm how I want.
With the above from the testing I have done it is faster than a stock assault, stock vr1 x 137, and I have beaten a few 850 Doo's as well so it seems to perform decent. Consistency is near spot on with instant rpm from -30 to -10* on a warmer spring day I would toss the stock Polaris belt on to get the sled to rev quicker if it got lazy.
Hope this helps guys.