I would use the acetate. IMO The "Condoms" Do not allow as much light through, so it'll be a little darker. I used a blue one on a vaccuum gauge (I bought it at Pep-Boys) And ended up taking it off because it wasn't as bright as i wanted it.
ditto. they don't look very 'incadecent' if you wanted an opinion.
if you want red, i would definately go with red acetate tape (you can find it practically anywhere--wal-mat, target, autozone, etc).
however, if you want blue...i couldnt find it anywhere. you might want to check a local art & craft store & see...but i have had NO luck whatsoever. you might have to go with the condoms if you want blue. OR you can get a blue 'neon' strip (i don't think blue is actually neon--neon is only orange i beleive--so blue might be xenon or something?
ah, anyway..eveyrbody calls them neon anyway). but at least you'd have adequate light that way (but it would cost more)