Yeah on other platforms removing the isolator and just using some heater hose is very common, and as far as cutting springs many people who have not actually done it will tell you "DONT DO IT" key element -they have not actually done it. lol.
when you are looking to just lose such a small about of height you can get away with cutting a tiny bit of the top of the spring off with a cut off wheel. you will 1. not generate the heat a torch would, which is one of the common comments about cutting spring (heat will alter the springs rate) and 2. if you look at aftermarket coils when they are installed and the weight is loaded the first couple coils are already resting on each other...cutting that tiny bit off the top is not going to reduce any suspension travel.
also the labor to remove the spring is literally 30 min. its not a lot of work.
I'm going to try removing the isolator and use some heater hose and see how it goes. As long as the spring stays put, that should get me SOMETHING.
I'm not afraid of cutting springs, I know it sounds a little mickey mouse but it's not that uncommon because springs can settle unevenly or have dead coils that serve no function. Like you said, if you're not using a torch, you're not effecting the spring as a whole, so it's all good.
Sadly the rear springs don't have dead coils, and the end coils are a smaller diameter to fit the isolator specifically and wound "flat" so they seat flat against the isolators. Removing anything from the top or bottom is going to effect it's functionality too much for me.
I think I've got my answer, I'll post back with results or failure, whatever happens!