A new door should not be hurried, and neither should the bill. The options below are the ways it can work. Jeff will go over them with you at the opening, in no rush.
Doors are best paid for without hurry. These are the ways it can work, so nobody has to rush a decision in front of the door.
A deposit to hold your door
A deposit lets Jeff set a door aside for your opening. He will not lend it to another room.
Payment on completion
Due when the door slides the way you want it to. Jeff will ask whether it does. More than once.
Card, check, or transfer
All welcome. Jeff prefers a handshake and a few minutes alone with the door afterward.
A payment plan
Ask. Jeff would rather you spend on the door than on the paperwork.