Yes this will work, Provided the dings don't go too deep in the carbon. Any depressed areas will have to be built up with a glob of paint. I did the same with a carbon hood on a car that was an oxidized mess. I went up to 2000 grit sand paper as my electronic polisher sucked and was doing more harm than good. So I ended up having to hand polish it. Trying to get a MIRROR swirless glaze can drive you INSANE. I stopped when I could read the serial numbers off a dollar bill but there was still more work I could do. There really isn't a point shooting for that on a kiteboard given it's use. Make sure the paint has a UV inhibitor or it may oxidize (turn cloudy white) depending on how the original board was built and what epoxy/gelcoat they used and how much you sanded through. If you're looking for AWESOME results ensure you spray your paint in a Clean area. (your garage is NOT clean, nor is your back yard) Lot's of dust and shit will fall on it otherwise . It's all correctable with sanding but will leave small imperfections that you (and probably only you) will see when polishing. I've heard wetting the floor in the garage helps immensly at keeping the dust on the floor.
It all depends on what your "good enough" standard is. I was working on a $1000 hood on a $60,000 black car with PERFECT paint under 1500 watts of lighting. But you can get good(ish) results if you just sand and shoot with a spray can. Oftentimes just hitting a lightly scratched board with a polisher makes it look "new enough" by removing removes all the white scratches from the clear. I'd start here, once you wet sand it can take a lot to make it look good again.
Or just say F it all and buy a 3M di-noc carbon sticker and be done with the whole process
As for gelcoat I don't believe gelcoat can easily be applied after the building is done, usually it's thick as hell and cured in the mold when the part is being built not something that is easily sprayable or paintable.
As for finish, many in the sailing community indicate a wet sanded finish is faster than a polished finish. To my knowledge it's really just superstition at this point. I`ve researched the topic immensely and never seen ANYONE present any data to support this. Other than the guy who just sanded is boat for 10 hours and said he could ``TOTALLY`` feel the diffence the next day on the water. ``just rub your hand on it, it feels WAY more slippery``
I`m not saying there isn`t potential with regards to CONTROLLED aligned surface texture (3m riblet film, denticals) etc which prevent momentum sapping eddy's from contacting most of the he wing surface. (this has also been proven by NASA) but I don`t think the wet sanding vs polishing has really been approached in a very scientific manner, so just do what you think looks pretty.
Study of random surface finishes from the aircraft industry has tested and quantified that the better the finish the less drag the object will have so without data to support otherwise, anyone telling you differently is just expressing an OPINION that is contradicting actual test results.
BTW yes I am trying desperately to goad someone for a response here to prove me wrong....
as I`m still laying out my race board building plans...
I need a flow bench.......