There is spring info/charts in this thread:
http://www.oople.com/forums/showthre...t=spring+chart
we have losi shocks & losi springs on our D4, you can see others have run them, Truman etc, hope this is helpful.
(if you get to the charts on the petit page, the shock oil chart will be helpful, many of the D4 setup pages use the cts number, ie 350 would be losi 30wt)