Heliplane
Thanks - unfortunately nowhere near the detail I need.
Page 14 onwards seems to give exactly what you asked for, an RPM setting relating to percentage power.
And as Monocock already said fly it and you will soon figure out what you need and what it does, 65% pwr is 2350 rpm with 8 and bit gph
Also you will probably find that when the aircraft was delivered new it would have come with the Lycoming engine manual that's most likely why the AFM is sparse on figures. Of course the other way is to get an AFM from another aircraft type fitted with the same engine model and see if they have produced the figures you want after all it's engine performance you are after so the airframe it is attached to is fairly irrelevant.