coilover/ride height help please

[noonzor]

i want to run a coil over rear for my truck, with a comp eng antiroll bar for added stability. so heres where im stuck. im not sure what coilover/spring rate to order, dont know how to weigh the truck since i only have pieces of it haha, dont know my ride height.
i dont have my wheel tire combo, although they have been chosen(funds). at which point do i NEED the wheels/tires?

so my questions are....

determining final ride height? whats good for a street/strip truck? what are others sittin at?
determining coilover/spring rate?
can i hold off on wheel tire purchase? or should i get them asap?

if more info is needed let me know and ill supply what i can.



Thanks Guys!

Kyle.