I have shot nothing but small vanes for the last 6 years on my hunting arrows (Easton 235 and 280 Diamond Vanes, Duravane 2.3" 3D vanes).........I shoot high speed arrows tipped with mechs and treat my bow the same as my 3D set-up. Why practice drilling X after X all season long with the 3D set-up and then switch everything over for the real thing? I just switch the pretty colored bow for the camo one and have at it. The only thing I change is that I up the arrow weight and draw weight a bit for hunting, I wind up with similar speeds and trajectory with even more punch.
That said, my high speed 3D style set-up is hitting much harder than many guys heavy duty rigs.
My typical set-up over the last several years has been 375gr finished arrows at 65-70# of draw weight with speeds between 295 on up to 315fps. I haven' t had a bow shooting under 75ft lbs of KE since 1996.

Shooting a rig similar to what I shoot all Winter/Spring/Summer at 3D tournaments really helps the confidence in the fall.

Since my mechs fly like field points I simply don' t need long fletch to stabilize anything.
Some of the small fixed heads like the Montec or smaller new Wasp Bullet, or Rocket Ultimate Steel etc. I' d probably try a 280 D. vane or a 3" with about 3-4 degrees of offset and see how they shot.
Larger cutting diameter fixed heads I would probably just go straight to 4" vanes.