I do own a spring compressor for disassembling and reassembling struts, but I have no idea where it is.
A long time ago, a crafty veteran taught me this handy approach. The compressed load of the spring is actually much lower than most people expect.
To put the assembly back together, use the weight of the car to compress the spring. If you want, you can also place two straps around the spring (one on either side ) prior to dismantling the strut. These straps then hold the spring compressed for re-assembly.
By using this technique, you can cut your time on replacing struts in half. You can replace them anywhere, like at the race track or in your drive way.
Lowering springs here I come!