Question #1....is it standard procedure to cut the vinyl at the point where one aluminum panel overlaps the previous one or is it better to heat the vinyl and conform it to the step? Second question...."remove and the reinstall screws" vs "wrap over the screws" method. Which do you prefer and why?
I like to start by making detailed measurements of all the panels on both sides of the trailer, then I make a full scale template and create the artwork based on all the panel widths and overlaps.
I print the wrap panels the the exact width of the aluminum panels on the trailer, including a bleed. Then install the wrap on each panel and cut the wrap along the seam of the trailer panel, it almost looks like each panel was screen printed directly on before the panel was put on the trailer.The only seams are at the panel over laps, I have NO wrap seams in the middle of a panel.
As for the screws, yes it takes more time to remove them, but IMHO, makes for a much more professional looking install, if you wrap over screws, sometimes the wrap lifts around the screws several years later (see example below).
One word of caution, I don't take all the screws out at the same time, I don't want the trailer to fall apart. Take out screws for one or two panels at a time, wrap the panels, re-install the screws, then move to the next panel(s) and continue removing screws, wrapping panel(s) replacing screws until one side is complete. This way the trailer doesn't loose it's structural integrity by taking out to many screws.