Their's no need to if you paint really. Scuff coats are not fool proof, easy or nessicary!
Like I mentioned I just over coat with a clear gloss to match the sheen on the profin mostly. Otherwise some of my colors are dull and ugly, it evens out the sheen and duco sticks fine to it. Simple solution to capping paint selection problems.
I buy my profin at a cabinet shop but it costs me a LOT more than 75 a gallon. I can get it by the quart at a local hardware store for 20-25 I think, it is a quart and quite the rip off but its not a 800 mile round trip drive either at 4+ a gallong in fuel. As few arrows as I make today paying a little more per quart is justifiable.
If you do white (or other light colored caps, I prefer yellow on my personal arrows, or light cresting bands) definatly DO NOT overcoat with profin or expect some to a lot of yellowing. A lot will depend on how many over coats you apply. more coats, the more the yellow will be visible. The yellowing on bare wood (no stain) is quite nice on doug fir and POC. I have yet to go back and try it on ash though I see those days coming near.
Bob talked me out of a true scuff coat years ago now. Its a headache that isnt worth the hassle. Again the waterbased is to even out the sheen and no other purpose, one coat is all I usually need. I prefer gloss (in all my sealer/paints). It looks nice and its the hardest of the finishes.
If you can find it, Sherwin williams opex lacquer mixed 60-40 or so for a cap is some good stuff. I had some but unfortunatly for us up here I have to buy a pallet of one color which turns into two pallets in a hurry after you thin it down. I cant justify it anymore. their was a time.
now if you really like fletch tape and/or a really HARD, durable by far the best finish....you should try the 'massey' finish. you WILL need to overcoat a time or two in clear water based before you can go over your cap/crest area again with the epoxy...but as a sealer and really a skuff coat their is NOTHING better!!! Its an amazing sealer. I used it for a couple years and had great luck with it. I dont like fletch tape as a hole however and stopped using it. Duco nocks on and the ends of feathers. I never did try duco'ing feathers on so I cannot say one way or another if it works or not. I'm sure CA glue would work well with this method if you, like myself, do not prefer tape.
Bewarned if you're a fletch tape user you WILL have issues eventually on profin!!! I had some non painted all wood profin sealed woodies two years ago and had almost every feather fall off in the cold. I should have realized my mistake when I started having issues in PA deer hunting. Mind you it was seriously cold on the bou hunt, Pa was 60's or so and I was loosing one here one their stumping mid day. Fletch tape IS a lacquer based tape. it WILL stick to some things. It works EXTREMELY well on epoxy. I dont think it was humidity in PA that bit me, it definatly was NOT humidity up here, temps wer pushing -50 with a crazy cold windchill. I did some research and came up with the lacquer based tape after all this happened. Fletching arrows over the defroster in the pickup by hand while you try to regain feeling in your extremities while a good sized bou herd pass's by camp is more frustrating than working for free while congress figures things out lol!!! When the wind died, the bou moved, and I stood their featherless....embarssing to say the least lol!