Hey Dan,
First off, thank you for taking the time to read through my thread and post and glad you appreciate/like them.
I try to keep them as clean as possible but it's never 100% perfect. Occassionally you get tiny bleeds etc that can't be helped or might get missed. I think most painters get bleeds here and there sometimes but the decent ones will clean them up/correct them. Like said, sometimes you might miss one..it happens.
I use my RCS liquid mask (

haha ) most of the time. Sometimes i will use vinyl (example shell I did using paint masks in the howto section on my site), sometimes tape, sometimes some vinyl cut lettering etc. Just depends on the job in hand. Mostly liquid mask though. Props to some painters who only use vinyl cut designs. Getting it to sit around all the compound curves of a shell is a whole skill in itself!
I sell createx which is waterbased but yes, the RCS paints are solvent based so 2k/cell thinners etc to clean out yer brush, yup. RCS candies and special fx are available but aren't up on the site atm. Should have them up within the week hopefully. will be available in 1 & 2oz bottles. Liquid mask will be in 8 &16oz shortly aswell.
Regards,
Jon