rolling a jet ski

the jet ski is an old 440 i started sanding it to get rid of the shine and smooth thing out. but being a jetski there are some deep scratches here and there.
is there a primer that can fill these or should i use some type of filler such as Half Time. also i plan on using the brightside paint you think that will hold up for the bottom of the ski? does this paint scratch easy? and should i use primer with brightside, if so what kind/brand

There is another guy on here that painted his jet ski. If you click HERE it will take you to his project. As far as the scratches, if they aren't too deep you could probably get by with using a high build primer then just sanding them smooth. Otherwise you may have to use some body filler.