DIY tinting isn't too difficult once you get the hang of it... I've thrown away enough crinkled tint film to know first hand 
I did the whole car myself with pretty decent results, no air bubbles but one or two small bits of dirt stuck behind one of the pieces. Also, I used wet film rather than the heat shrink film.
A spare pair of hands would have been a big help as you want to keep the sticky side of the film soaking wet, it can be tricky to peel and spray at the same time. That way, if it does fold together it won't get stuck and ruin the film. Keeping the film soaking means it's also easy to pull it back to remove any trapped air bubbles.
It's a fairly logical process once you get the hang of it. I did it on fairly cheap and tatty cars so wasn't too fussed about it being 100% perfect. Certainly wasn't a bad job though.
For fluid, just use fairly weak washing up liquid in a spray bottle.
I did the whole car myself with pretty decent results, no air bubbles but one or two small bits of dirt stuck behind one of the pieces. Also, I used wet film rather than the heat shrink film.
A spare pair of hands would have been a big help as you want to keep the sticky side of the film soaking wet, it can be tricky to peel and spray at the same time. That way, if it does fold together it won't get stuck and ruin the film. Keeping the film soaking means it's also easy to pull it back to remove any trapped air bubbles.
It's a fairly logical process once you get the hang of it. I did it on fairly cheap and tatty cars so wasn't too fussed about it being 100% perfect. Certainly wasn't a bad job though.
For fluid, just use fairly weak washing up liquid in a spray bottle.