You will find that it works all the ways you mentioned. Some guys do paint and are artistic, so they can do it all. Some will work with a shop or painter to lay down the color first and clear then they do their work and then the painter clears it and cut and buff. Some will come to your shop and just do what ever you want them to do. As far as cost you will find that it is all over the place and that there is no standard for charging for this kind of work. Most will tell you a flat cost like I want flames and he tell yous you 1500.00. Watch out for the painter that tells you sure I can do that but doesn't have any past pictures or cars to show you or past customers to talk to. Hope this helps and takl to some of the guys cars you see and find out who did theirs. Good luck