A strip and repaint typically takes about 3-4 months.It sounds like alot but alot goes into it.How many coats is painters preference.The directions say 3 coats of basecoat and 2-3 coats of clear.Some colors dont cover well so 3 coats of basecoat is unreasonable.You just have to spray until its covered and then one or two more after that.I like to buff the snot out of a paint job so I always put 1 more coat than the manufacturer recomends.When you buff a new paint job you have to sand it with a fine grit sandpaper first,usually 1000-2000 grit.During that process 1 coat usually gets sanded off.Thats why I usually add one more during the application.Its also painters preference to use basecoat/clearcoat or just a single stage urethane.I use base clear if its a mettallic paint or if there is some stripes(clear makes it so you cant feel the line on the edge of the stripe.)Theres nothing more frustrating when your painting,for example black basecoat clearcoat,and on the last coat of clear a white speck falls on it.The you gotta repaint the whole panel because of that.Singlestage urethane doesnt have those problems.
Another thing to look for is if you are going to have the car disassembled for the work or not.I dissassemble everything.It makes for a nicer,cleaner looking job.At very least if you dont want the car dissassembled,change out the door bushings.Doing that after the paint job will be very nerve racking.Sorry Im so long winded but I used to do alot of c3s and know them well.This is not a sales pitch.