even though i am a staunch advocate for bareshafting, i do find myself drifting away from it.
i am almost inclined to say- get as close as you can, based on the charts and personal experience.
fletch up 6 shafts, 3 with broadheads 3 with field points.
and try group tuning- its a very effective method if you are reasonably close to start with.
what got me thinking this way, many years ago i was shooting shafts that were 15# too weak in spine( lack of knowledge!!)
and my field point's grouped well, they flew well- and i put broadheads on and took deer with them. one day i decided to practice with the BH's and they all grouped consistently to the side- both groups were good- but just two distinct groups.
so now i broadhead tune, and if you dont hunt just get some vented 3 blades, they will fly well and less likely to plane while your setup is not perfect.
and i was doing this all at about 15 to 18 yards