The front I got here is about 16.5" - 20.5" (from loop t-bar to end of thread. I guess you gotta take an inch or two from both of those for the top bushing.
I wouldn't put much faith in re-using them for your SAS. For refenence, for my front, I need a 20"-29" shock. But this involves custom mounts tho. I don't think the stock 4" of travel is gonna work.
Robb