dual/stacked springs on the 5th arm?

I've noticed quite a bit of talk about running 2 springs on the RF lately. I kind of grasp the idea behind that and a very general idea of what it does.

Sounds like it could be a good setup for a 5th spring if done right... has anyone played around with this before or have any advice?

I played with it a few yrs ago i think in the dry slick you can find some success with it we were on a hit and miss deal. We quit playing with it due to being in a point battle and were losing ground. Pm me and i can tell you more about what we did.