lowering the truck and questions.

[1969stepside]

So i have a 1969 c10 that i have lowered. i used drop spindls in the front 2inch maybe 2-1/2 with stock oe gm springs. in the rear i have eibach rear lowering coils 3 inches. the tank has ben relocated to the rear and it its a stepside bed. well the back of the truck with the bed on it sits a little hig for my taste. i want the truck to have a level stance or even stance. do i need to put a 4 inch spring in the rear or something else. should i use a 1 or 2 inch lowering block? i def do not want to c notch the frame at all. i dont really want to mess with the geomotery of the suspension. i also keep seeing pinion angle on a lowered truck i know what that is but not sure what to do about it. any help would be welcomed.