Shock Length and what brand is best?

[jughead]

72 Blazer 7 inch lift in the front(6 inch spring 1 inch zero rate) and 10 inch in the rear(6 inch spring and 4 inch shackle flip) and sits very level despite the diff in lift from front to back. Now I need shocks. What is the best way to measure for this?

 

[obijuan]

i have the rancho 9000 in the front and 5000 in the rear and i like them alot, my 6 inch front was ~34in extended and ~20in collapsed im not really sure but yours should be a little longer than that for 7 and 10 i just dont know.