I run the GK SK 43s at pressures between 30 to 40 psi. The tires lose maybe about 5 psi per week at most, set up tubeless with Stans Race sealant. These tires were really quite hard to get on my 21mm internal rims, and I needed to use an Airshot to pop them onto the rims, as a floor pump did not provide enough air volume quickly enough. Once seated, though, the seal was fantastic and quick with Stans. The tires do stretch out after that initial seating. After six months, I did a sealant check and top off, so I broke the bead and took the tire off part way. It was way easier to do this than the first time around. I still needed to use a lever to get the tire off, but I was able to use my fingers to get the tire back on after adding sealant. Another Airshot got the bead seated again, and the tire sealed up perfectly once more, good as new.