I've got 22,000 miles on my 2015 K1300s MS. All tires so far have been Pirelli Angel GT's after the stock M3's wore out. I weigh about 200lbs and usually ride solo.
I've tried a bunch of different tire pressures, and what I've come up with so far is "use 38/42 psi".
The front end feels a bit vague with 36psi in the front, but MUCH more precise steering with 38. Let's say you come into a corner with a lot of gravel, but a 3-inch wide clear strip through the corner. With 36psi I couldn't guarantee I'd keep the tires exactly where I needed them, but with 38 I can. I've tried a bunch of different pressures in the rear and didn't notice a much, if any, change with higher pressures, so I leave it close to 42.
Years ago at a Michelin seminar at a BMW national rally I was told that the proper cold tire pressure was whatever it took to have the front raise 8-10% and the rear 10-12% when hot. That is, measure tire pressure, then go ride normally, and then immediately check pressure when hot. The pressure should go up 8-10/10-12% due to heating. If it goes up MORE your tires need more air (to stiffen them), and if it goes up less then bleed some out. The faster you ride the more air you need in them. This is for more-or-less normal riding, not track racing. The stock pressures go up more than the above percentages for me, but I'm not sure if that old rule of thumb still applies to modern tire design.