I do both Regimental and Wing scale depending on the battle, and both
work well. I do use the original V&B AWI recommendation of reducing the
number of men per SP. For 'Regimental' scale I find that 250-300 men per
SP works out to each linear stand usually representing a battalion,
which 'feels' right for me. From what I've been told by local AWI
experts battalions were often the core maneuver element during AWI
battles.
For Wing scale 75-100 men per SP seems to work well.
One thing I've found is that when converting historical OBs to V&B OBs
you have to use a little of your own judgment and be flexible when
rounding your numbers to SP. Give a little here and there to make your
stands represent the units that were maneuvering in the historical
battle. I've found when I'm draconian about sticking to the exact number
of figures per SP that things sometimes don't end up as historically
accurate in the game as when I use a bit of common sense in creating my
OBs. Play testing also helps a lot to get your OBs just right. I'm also
not afraid to adjust morale ratings according to how a unit performed in
the battle. Case in point, for Freeman's Farm I rate Morgan's Rifles
Morale 6, Sharpshooters. Morgan's unit performed feats in the historical
battle that are impossible to replicate in V&B, but I give them the best
chance I can by upgrading their morale and giving them the SS rating.
I'm not very familiar with FIW, but Byron is and if he thinks my games
map well to FIW, I'd support his recommendation. Reduced SP in wing
scale works very well with AWI and gives a good 'feel'.