99% sure I will do the dry method.
Really don't like the idea of wetting adhesive stickers, but having said that youtube posts sure seem ok
Will keep you posted and take pics as I go
A tip on decals.. they are not a solid sheet of polymer. they are in fact slightly porous. I apply large sheets of vinyl 1200mm wide to sheets of aluminium composite panel ( has a colourbond finish) all the time. A standard sheet is 1220X2440mm. Vinyl comes in 1220mm wide or 610mm wide. To be able to put down 1220X2440 and get it exactly right so the top and bottom edges all meet, you HAVE to do this wet.. its impossible to do dry. Its also a lot easier to get air bubbles out of wet.. if dry you have no choice but prick the bubble to let the air out unless its right on the edge where you can push it out.
The water ( with a drip of detergent) is squeezed out from centre to edge.. this can be done with a real cheap car window squeedgy from Crazy Clarks.. costs $2!.. it works perfectly.
If put out in the sun for an hour, the vinyl is completely adhered and completely dry... any retained moisture is sucked out through the vinyl...don't like the sun?.. No problems, it will still dry perfectly but will take a day or two depending on ambient conditions.
I do this for signs that go outside... nothing peels, vinyl stays on and the longer it stays on the harder it is to remove.
Your decal is a print on vinyl.. my signs are either coloured vinyl or print on vinyl with laminate finish.
You will get better results and your job will be a whole lot easier if done wet... it will also allow you to move the decal around a bit for registration.
Even the most experienced sign manufacturers will prefer the wet method for something that is 450mmX1320mm unless its "Easy Apply" which yours wont be.
Do it wet..
Gav