Pineteam - remember there is no great harm in setting a FPA and it being slightly too steep. It is permissible to go below profile on a NPA - as long as you are above the floor limit for that distance. Set what you reckon (a good start is to start with the FAF correction of +X%, increase the FPA by X%). Then adjust accordingly after the corrected alt / distance cross check. Watch the floor limits like a hawk of course (if any) and If you get a bit low, reduce the FPA or vice versa.
I normally have the corrected altitudes for the on the day temp for the chart distances to hand and get the PM to call high or low off them. I can tell you it works just fine for LNAVs to ISA-57°C.
Last edited by compressor stall; 26th Mar 2020 at 23:29.