Grand Prix 250
Main Motorcycle: '18 Street Triple R
Join Date: Sep 2018
Other Motorcycle: '90 Honda VFR
Extra Motorcycle: '03 KTM 640 Adventure
Super bummed to see the trouble you've had, Joseph. I looked at it last Thursday night and just said "no." Put it right back on with the intention of tackling it again with at least 4 hours free. It looks something like a co-molded part, so there's no "peeling" off. And from what I understand there are grippy raised parts of the throttle tube that also need to be sanded down - for feel and also for diameter.
One thing that I see from the photo though, is that it looks like you didn't unscrew the throttle housing, to remove the throttle tube/grip off the handlebar. Don't see that it will make the actual job any easier.
Xorbe, the throttle tube is plastic but has the rubber grip overmolded or co-molded to it - it's not a glue job that you can heat/peel/cut off. The thread on the Oxford heated grips install talks about it some more. According to all those folks it is doable, it is painful, and it is not something that anyone wants to repeat.
The left side grip is also on a plastic tube, but is not similarly molded. As Joseph said, you pull that thing off easy as any other, and a new grip just slides on.