77 KZ1000 shocks, which one's ?

I have looked through the posts and found several posts relative to the rear shocks of my KZ but still need help. I have looked at several bike part supplier websites and e-bay and found shocks but they do not match the dimensions, eye to eye, that mine do. 1st question, is the exact dimensions really that critical.
First I should mention I have a Harley hub on the rear which makes it a 16" rim versus the stock 18". I'm getting measurements from 13 1/4" to 14 3/8" for the replacements. My shocks actually measure 13 3/4" eye to eye. Next, does removing the springs and painting them worth the trouble in the long haul? From what I have read, here in this forum, taking the shocks apart is somewhat of a chore and really no standard for doing so. My springs are very rusty but the shocks appear to be in good shape, as far as the chrome goes. Whether the shock itself is good that will be determined if I can get the shock itself apart. Also if anyone has experience with painting the shocks will the paint stand up to cracking and flaking due to the springs movement. Thanks as always for the help.