i can't remember what i used, but here's a link to figure it out:
http://www.monroe.com/catalog_lookup/ocl_default.asp
when you're laid out measure how long it would be at the shocks collapsed legnth, then air it up & see what it should be at its extended legnth.
there's not really a "one size fits all" because i have tube arms & where i welded my shock mount might be different from where you'd weld yours. also i chose double loop style, but some guys like the loop/stem...although i think there'd be a better chance of those binding up if the geometry isn't perfect...but to each his own
once you have the part number you can go to auto zone or wherever & order them that way...if you can find someone that knows wtf they're doing. at my auto zone if you don't have the year/make/model their brains start melting & they give you that deer in the headlights look, but they CAN order parts by manufacturer name & part number!
good luck man...