the paper tape i use is 3M Micropore surgical paper tape - i purchase it from
http://www.dragon-fly-designs.ca/shop-other.html - it is great stuff! - i never thought of using it to mask off area's what a great idea!
your tape/jagua removal esperience sounds extreamly painful!!OUCH -> wont catch me doing that! the micropore paper tape i can almost describe as - soft cotten fibers woven to make a strip - with a very light tack adhesive backing - it is sticky but isnt like "waxing" your body.. its pretty painless to remove.. and holds everything in place.
i find though (good and bad) on warm days (or warm bodied people) the paper tape really forms well to you- and the design and it can be difficult to "find the edge"
over the years of doing henna.. this is my favorite method for my palm too- since i find that if i use the tp and sock method - i still manage to clench my hand into a fist and make a big mess... or my hand sweats and the paste adheres to the tp and i is a real pain to remove... so i use the paper tape - everything holds in place.. i dont have to worry about anything, and it all just peels off perfectly
i also like those little cotton gloves you get at the doller store or where have you (atleast here in canada) i'll use those at night too..