One of the major advantages of bare-shaft tuning- it takes feathers out of the equation. When you're bare-shaft tuned, the function of the feathers is more to clean up your shooting variations than anything else. Once, shooting the Howard Hill World Championship in Wilsonville, AL, a thunderstorm soaked us all. With my feathers plastered down, I still managed a good score, when others were hurting.
With broadheads, it's even more important to have the right spined shaft. I can use 3 4" parabolics on my target arrows, but I go with 3 5" shields (trimmed until they're quiet) with broadheads.
Don