i would say use some more fiberglass on the low areas to even out. like the front part of the enclosure where the port is at, it has a couple of waves that you may want to bring up to the level of the other side. so use some more fiberglass, in areas like those. once it looks like the enclosure is pretty much even all around and your done fiberglassing then go ever the whole enclosure with like a 30~40 grit sand paper on an orbital sander. and even it out even more. if you find spots that are to thin on the surface due to the rough sanding then reinforce them from the back of the enclosure with more fiberglass. till you get the right strength. now that every thing is pretty even, now you're ready for the filler, you don't have to lay it down thick, since you really want to use the least amount of filler as possible. knock down the high spots of the filler, while is still kind of warm but not tacky with the 30grit paper. just to make it easier on you once its dry then sand with 80, 120,200. then you should be ready for the primer. if you have a good finished on the filler then priming it will be easy. when sanding the primer you don't need to go any lower then 400grit.
now paint show every little imperfection and hide nothing. so sand till your arm is tired the some more. once you're ready for paint, i use enamel paint. i suggest you get the one with the tip that sprays at horizontally or vertically it can be turned manually instead of the tip that sprays a dot. if you're going to use a can. start from the bottom up an on each pass cover 50% of the first pass and so on. dont try to paint the hole enclosure on a couple of passes do it in layers. do a light layer at first wait a couple minutes like 2 minutes then do another layer and so on till you get the desired finish. let it cure for at least 24hours before you decide to touch it. if you're not happy with the finish you can always wet sand with like 1000 or 1200 grit as the most aggressive, and 2000- 2500 the least aggressive to final grit. soft foam or rubber backing pad so that the paper may be wrapped around this pad (not around your fingers!) once you're done buff it.
a grate place on info about fiberglassing is
fiberglassforums.com you'll find allot of expert there that can guide you from where you're at right now on the enclosure to finish.
that where i have gather most of the info above.
and here is a link i found on
wet sanding
some frequently
asked on paint questions link
sorry for the long post.
looking good so far.
good luck and keep us updated.
laters