Having just used Scale Coat II, be aware that it takes a lot longer to dry and fully cure than Floquil does.
Scale Coat also dries to a gloss finish - fine for decaling. A top coat of Testors Dull Coat or something similar that is alcohol based will reduce the shine and not harm the paint
For masking, I've used Tamaya (? Never could spell that name correctly when away from the workbench) which has a thin, reasonably low tack fine-edged masking tape which worked very well over Scale Coat II after it had cured for two or three days.
I've found that the commercial blue and green masking tape has a higher tackiness which can lift relatively fresh paint. One way I found to use it when needed, is to run a strip of it on a piece of glass rubbing it down well.. Then cut what is needed. Pulling it off the glass reduces some of the tacky-ness.