Apologies for still not quite seeing what you're saying regarding the hooked tool. I would remove the shock absorbers from each axle tube and carefully allow the rear end to then "open", decompressing the spring. I would remove the right hand bolt from the spring bracket, loosen the left hand bolt and let the bracket pivot to remove the spring.
At this point, I will replace the boot - which is the reason for all of this! With that installed, I'd basically reverse the order I noted above, perhaps having to pry the bracket over to where the right hand bolt hole aligns. It sounds as though this is where you are using the hooked tool - to instead lift the bracket to align the bolt? If so, what is grabbing the hooked tool to lift it? Your hand?
Also, I'm now considering whether I need to remove the exhaust or can just release at the rear and allow it to lower some, out of the way. I guess I'll have to see?