artists_beware | Big Commission, Want some Protection.

EDIT: Sounds like I'm good to go :3 Gunna ask him for a deposit, get in on that money up front idea, and then get that contract rollin. To protect him an me. :3 Thanks folks!

Hey A_B

I don't know if this is outside your bounds (obviously we'll know if this gets posted, or if it does not) but, I wanted some input.
Now, I don't usually write up terms on commissions, however, the situation has come up where a commissioner wants a Series of images and is willing to pay out a large chunk of money. This person has commissioned me before and has paid me upfront, and graciously tipped. I have been more than willing to take his commissions and to work with him happily.

THIS HAS NOT CHANGED.

What has changed is the amount of money, and time.

He would like a series of 7 images and has offered to pay me $500 to do it, to be completed for May 1st.
I want something to protect me, so I could at the very least so I could drag him into a Civil court room if it came down to it. I'm no good with words, and I know there's a friendly bunch of internet lawyers out here who could probably help me come up with something, to say the least. Just an agreement, signed and dated by a notary in both cities. Photocopied so we both have one.

What should I do? How should I phrase it? What can protect me if he's wants to back out and I've finished work on one or all of the pieces?

Annnnnd if you know who is reading this, I posted because I wanted input. Not because of anything you've done, or haven't. :3 It's because of all the things I've seen happen to people, and that big projects have flopped on me before.

I "know" the commissioner fairly well. (as much as you can know someone over the internet) but I've seen people been scammed by friends in the past. I do not want it to happen to me.

Looking forward to this project, but apprehensive about the costs
Rhars