I've been fighting the GRCS for years! How it never occurred to me to just hang it from a rope is beyond me.Sounds like you are rocking it.. Men are brutes to our own detriment, our bodies pay for it later if we don't learn to ration it. There are many tricks to do things better, maybe slower, but slow can be efficient as the days burn to weeks, the weeks burn to years and so on. I've thrown my back out rolling a log out of a crater by hand, with a peavey laying 10' away. The issue is while I'm more than strong enough to do it a few times, I couldn't do it for a few days in a row (lots of removals that week).
As for setting up the GRCS solo, It's a pain in the ass and barely possible for most. A trick is to have the rigging line and block installed first. Assemble the GRCS on the ground at the base of the tree, next take the working end of the rigging line and tie it off at the base of a tree. Next load the control end of the line into the GRCS as if you were winching something, rock the handle back and forth until you can freely spin it, winching the GRCS up the line. This will allow you to have it held in place as you position it around the tree. The only part that is hard solo using this (sometimes clumsy) method is getting the strap tightened enough. There are countless little tricks like this, that many may never know about. I picked this one up by a YouTube video comparing the GRCS to some other winch.
It's about the details, I've been to quite a few comps but never had any desire to compete. I pick up way more by watching and looking for details. Taking the tail of a foot ascender strap and tucking it into the boot laces (DUH!), wrapping the bungee of a knee ascender above your knee and clipping it back to itself to stow it in place. I bought a 261C for a woman who worked for me for a while, she had a hard time starting any of the other rear handle saws on the ground. The trick is to eat, sleep, and learn all these details. Every tree is a puzzle, there were many times when as a employee for a veteran climber of 40+ years he would lay out the work plan, which certainly would work, but a fresh set of eyes found a simpler way to solve the puzzle.
I got a chuckle out of @Lampyrid being excited about the power pruner. That is one of the only tools we use that really requires serious exertion and upper body strength.
Every other saw allows technique to take the bulk of the work and risk away from your body, but there's not really any way to avoid slamming the pole to the ground or keep giant spears from impaling you besides muscling it.
I know they have those sling things, but I've always found they make the work more difficult.