I have done countless very large decals on the side of our trucks (like 3' by 6' monstrous decals). I have made more mistakes then I'd like to admit. Tried soapy water, isopropyl alcohol, different mixes, etc. It's very frustrating to have to peel a large decal off
Anyway, just sharing my experience. What I finally found that works perfect every time is plain old windex. It takes longer to dry but just apply a little squirt to either surface (fine mist on both back of sticker and screen) place it where you want it, squeegee it out and let it dry for 12 hours or so.
It takes longer to dry then I'd like but the result is 100% success rate. I actually just did this the other day to a Deep 6 computer, just let it sit overnight. You have almost an infinite amount of time to adjust just where you want it, and everyone has windex on hand.
Good luck
@LFMarm!