I wouldn't necessarily run yet. You just have to finish selling the job right. As far as material goes, give him a list of stuff he can supply, basic stuff, pipe wire disconnects etc. and tell him it is impossible to give a complete down to the last fitting list. Then ask if he would rather have material left over or have you supply the little stuff. If he would rather have material left over, put in order like you are stocking the truck. Otherwise you supply all the misc. and let him get the big obvious stuff.
For the time side of it, be very clear that how long it takes is what he gets charged. Resist giving an estimate too, because as others have said he see that number as a "not to exceed" amount. If you do have to give an estimate shoot it way high and when they "what!!?? why so long long?!?!" tell him "well it could be less, lets see what it comes in at" and if they keep pushing for an estimate make clear that this not how T&M works, if he'd like a bid you can put forth the time to sit down and thoroughly figure the job, but then it will be a fixed bid. Then be clear about what is included so you can easily identify extras.
The problem is that most people like this want it both ways. If it goes long they want bid, if it goes short they want T&M, but they will wait until the job is over to make that decision.
But, on the other hand, sometimes they just need a little time and interaction to build up trust and then, because you took the time to work with them and consider (still try to avoid their way, but try to ease them away from it) doing things their way, the next thing you know, you have the run of the show over there. Good luck.
