Well if you will remember when I was running the FLM chassis with monoblock in a very similar setup I was using both 8 and 4 supershocks.. For some reason I wanted to be able to drop my truck from 4 feet flat and not have the chassis touch the floor. I was obsessed with this for about 5 months. After trying every shock on the market(and not on the market) I decided I was crazy and wrong for thinking these things. But I still wanted a big shock body heavy oil and fairly good springs. I ended up with 16mm buggy shocks. They are huge.
They have 30wt in them (alot of it) and the springs are medium hardness. I would like to try 45wt oil next time in these. I love them with 30 though.
However you I see now and you seem to know what you are doing. Yeah 50wt sounds good. Gee half way down is alot at the height you are running. We probably run similiar ride heights and I would have to say turn up the shocks preload collars. (I should say turn them down.) Mine only sags slightly. The front sags to where the shafts in the suspension are level and the rear sags to just above level.
It was so hard for me to picture and conceptualize the truck and how it reacts while in motion. You have seen and felt the donkey kicking and know it best.
-Zack