How far can you reduce the RNP down to using the FMS is the 737?
When I was flying the Dash 8 with PX it was drilled into the SOPs that the FMS RNPs were set to 0.03 if I recall correctly? And we were encouraged/taught to manually set up the VNAV profile for every approach which were all pilot calculated, not published or approved. Lots of potential for error in that little excercise, I always monitored the **** like a hawk as it was fought with danger in my opinion.