EGT's vary from machine to machine....but assuming your probes are where recommended (100mm from piston skirt, or 85mm from exh flange...?....I think?) 1250 is about max. My AC ran better around 1170.....my Doos seemed to like 1200-1250. (BTW...pure aluminum melts at 1220 F)
It's usually better to start cool and watch what the plugs and wash does as you lean it down...determine you own optimum temps. You'll find that in order to keep a "snappy" midrange, your partial throttle temps will be higher than your peak WOT temps. Doo's are famous for a lean midrange.