I use Krylon spray cans almost exclusively.  I haven't found any paints yet that will harm the Rigid Vinyl, but always test on scrap first. Water based paints have not worked well for me.
Make sure you wash and dry the body well before painting. I use dish washing detergent.  I have always painted the outside of the fuse but some people like to paint inside for a gloss effect. This can make assembly difficult though.

I use medium viscosity CA and Accelerator for all of my builds. Thin CA will run very easily so avoid it!
I have used vinyl cement for swimming pool repairs. It does work but dries very slow. Epoxy will also work but again I like faster results.

Cutting and Trimming:
Regular shears work fine for cutting. Curved canopy shears are very handy to use also. An Exacto knife or Scalpel works well to cut out openings.

I use mostly after market batteries.  A 10C rating or better for better flight performance. I have also used 3s batteries in both my CX's and Lama's without adverse effects. DO THIS AT YOUR OWN RISK.

Webbing is caused by too much plastic being pulled into an area over the form. I do everthing possible to avoid this. Sometimes a small web will occur though. To repair a small web glue the part on the inside covering the whole web. Let the glue dry then trim off the web and sand it smooth.

I use masking tape for delicate surfaces. You can trim small strips to bend around areas. Also putting on a larger piece and then just trimming it with razor blade around the windows works well.
Make sure you mask the windows on the inside before you paint. Also spraying a light coat of clear before spraying your color will prevent bleeding under the tape.