I don't do wraps, so I am not sure how you would be using the 1S.
But I am a sign painter, and I use 1S super gloss tinting clear when I can get it.
It has never yellowed on me but it does have a very slight yellowish tone in the can.
I use it for varnish shades (where you add a drop of color to it for a transparent natural drop shadow)
I think you may be referring to the UV clear in the white can.
http://www.1shot.com/home.html
(click on the products link, there is a clear coat option)
That is a different makeup than the tinting clear and dries much faster.
There is a matte and a gloss version in the aerosol, both which crinkle when sprayed over regular 1S lettering enamel.
The kind in the can seems OK but often has a sticky feel even when dry.
I have never seen it turn yellow either.
I am not a Frog Juice fan. I believe that is what is inside a Seal-It pen, though.
Love....Jill