Give it a rest......
That's it... we're taking away your Rotella T!!!
Two years ago I called and asked the difference between the GT rated tire and the same tire non-GT. I left a message and a guy called me back a couple days later. My bigger question was why the non-GT had a higher weight rating (admittedly only one number... but still...).
The answer he gave was that GT tires have a tendency to heat up and stay heated up.... long hours.... lotsa miles... and generally heavier loaded than other street formats. Other street formats tend to warm up and cool down and never put in the time or distance.
Could've been a salesman for all I know, but it made sense to me. Put a set of Angel GT's on the ST1100 and I believe are still on it. (YMMV)
For the FJR, I just received a set of T31 GT's. I went by watching opinions of others and what riders more my style have found useful. The tires I have on it now are old, trash, and need replacing, but I'm going to sort out my suspension issues at the same time so I don't ruin a new set of tires.
But... truly... the only way is to try a bunch and see what works.