Have you considered the Tusk spring compressor? It's about $35 from Rocky Mountain ATV, arrives in a small metal box with some plastic jaw protectors to keep from scratching the new spring when it's being compressed. I didn't use them. The compressor is the screw type; I had three different configurations of these for auto use but all were too big to fit comfortably on the KLR shock. Rocky Mountain has a video of the product in use; all I can say is that it works. You need a bench-mount vise, clamp the top of the shock in the vise, hook the compressors opposite one another (after applying grease to the threads) with the bottom of the shock upward. The compressor screw is contained in a metal enclosure that you hold with a crescent wrench while tightening the screw. I used a 1/2" rachet with a stepdown to 3/8" and a 6" extension to clear the shock, a 3/8" rachet didn't give me sufficient leverage. Six twists on one side, go to the other compressor, do the same. Repeat. Over and over again.
You need to compress the spring until the spring retainer collar has about 1/2" free play. Push the shock bumper down on the shock shaft and then you can remove the collar. Once it's out of the way, loosen the compressors until they can be removed then you can lift the old spring off. Do what you want with the shock if you're rebuilding it, otherwise drop the new spring in place, hook a compressor on each side and tighten it down. Takes about twenty-five minutes time total. Watching one of the YouTube videos on KLR spring replacement or the RMATV instructional will clarify what I've described.
Note: I used a small pair of needle-nosed vise-grips to remove and reinsert the collar. Never had any indication that the Tusk compressors were coming loose--something I couldn't say for trying to use automotive devices--but I don't care to put my fingers into a dangerous area around that spring. Eye protection is also a must.