you must be doing something wrong if your tearing it and putting holes in.
on what i assume is a clio roof, with avery (1900 i assume)? then you shouldnt need any heat at all. the material is made to stretch so u must be pulling way too hard.
the avery 1900 is a great vinyl to use, im doing a partial wrap with it tomorrow in fact. dont worry about the finish straight away unless you have creases, its so easy to say to yourself it doesnt look too bad but when you finish the crease will stand out like crazy, sort it before its too late. after a week or so all the little bubbles/imperfections will be gone and it will look great.