I guess it’s a question of what your mixed terrain looks like, and how punchy your riding. I’ve still got the front GC on since I bought the bike, its got 4000km of southdowns on it (almost all off-road) and just starting to think of swapping (but maybe i’ll drop another couple of psi). i’m very much a tyres on the ground rider, but do like a fast flowy singletrack descent. the only issue with the GC is deeper slop, or glassy leaf cover. not sure that lower pressure is going to help there, but not sure I want anything more aggressive cos it’ll slow me up everywhere else. If I do make a change, I’d probs go nobby nic. On the back I am still getting away w a fasttrak, running it 18ish psi max (would usuallyhave put a nobby nic on the back by now, but got given a pressure guage and surprised what i can get away with), and it’s finding lots of grip, even on greasy downs chalk ascents, but gets a bit squirrelly on faster muddy rutted terrain, and off camber is a bit exciting