You definitely need softer springs for your Firestorm's aftermarket shocks. Having the shocks somewhere mid stroke, while RC is fully loaded out with battery, would be optimal. I prefer having my RCs at arms level/"bones level". What shocks are they?
55wt shock oil
...that seems a bit thick for general bashing IMO. Of course, it all depends on the pistons being used, and the performance that you are after. Too many variables without seeing how the truck handles and what terrain it's on, and what shocks/pistons are used.