Wow,those shirts look amazing! Kudos to you!
I've done some stencils myself with spraypaint,not on fabric though just canvas. Unfortunately freezer paper,as far as I know,isn't for sale in over here in The Netherlands
...but I'll think I'm gonna buy some from ebay.
Anyway...I was wondering how you got the layers lined up so well? Do you have a technique for that?
Also what brand of fabric paint do you use?...do you thin it with water or just apply it as it comes straight out of the bottle? Would regular acrylics+textile medium work too (also on the long term)?
I don't really have a method for lining up the layers. I just try my best! And besides, if you don't get it exact, its not too big of a deal, because you can always go and clean it up at the end. Fill in where ever it needs filling in and whatnot.
I use Tulip Soft Fabric Paint. I don't water it down or anything, I generally just squirt some onto a paper plate and dab it on with a little sponge that you use to put makeup on (those triangle ones for foundation). I haven't used the acrylics and the textile medium yet, though I do have some that I've been meaning to play around with.