4" feathers will give you very good arrow flight with BHs and FPs. So you technically should be able to hunt and 3D with arrows set up the same.

If you really get into it, and want to try your hand at open class 3D, you will find many of the shooters use smaller vanes and featers (2" or so). If you want to eek that last bit of speed out of your rig, this might be the way to go, however they would no longer be suitable for hunting.

As for the color, it really is personal preference.

I have been through a number of transitions over the years
Vanes:
2 yellow 1 green
2 red 1 white
2 white 1 red
2 Orange 1 White

Feathers:
2 black 1 red
2 flo pink 1 flo yellow

I have found that of my choices so far, there is really nothing in the woods that is flo pink. This makes locating my arrow much easier after a shot, or if I happen to do a " fly-by" on a 3D target. Yes I do take some ribbing about the pink color, BUT, I can see my arrow flight until the end of shooting light.