Re: Should I use carpet or non-skid paint?
IMHO carpet & water shouldn't go together. Boat manufacturers use it for the reasons Marquette stated: less prep work, cheaper and faster.
I just purchased a Glastron SSV 170, bow area is fiberglass non skid floor, cockpit area is side to side carpeted. I asked the dealer before ordering it if Glastron could ship it without the carpet, and got a NO for an answer. I checked under the carpet, and I now perfectly understand why: it's a non finished fiberglass floor...nasty.
What I intend to do when the carpet is trashed, is to have a fiberglass shop do a non skid floor for me. Yes, I know it's expensive, but it's a lot easier to clean and maintain, and will last a lifetime if properly taken care of.
In your case in specific, I would check the floor condition, and maybe, you can get away just by painting it with the non skid paint you mention.
Just my $0.02
Cheers!