Technical Rear frame rails under banjo

Trying to save and utilize bed compartment size, so.....also need to figure out the triangulation of 35-36 radius rods. and rear crossmember

 

Are you talking under slung? If so, why the kicked up frame rails? What spring and crossmember do you plan to use? Not sure what triangulation you are referring to, but I'm thinking you need a pretty solid overall design first. Lots of us are using 35/36 radius rods and have done threads on it, myself included. But I don't see it working with what you appear to be doing. Search 35/36 radius rods.