Nose butters on snowflex are possible
I wanted to try nose buttering the jump at Woodward but apparently nobody had tried it before so I gave it a shot...and it works! Its definitely a bit sketchier as its harder to modulate your speed/spin on snowflex. Also, your skis tend to try and come out from under you but this naturally helps set for a cork (or even underflip).
If you get over there, give it a shot! Just be careful not to set too early, you're more likely to hit your head as your feet come out from under you pretty easily.