Matt
A few suggestions I've learned.
NEVER do T&M or "not to exceed" Unless the job is only going to be about half a day or less.
BECAUSE, customers WILL get picky about your phone use, coffee, how long it takes compared to what his friends said it should, layout and design time, shopping for parts, the list is endless. The bigger the job the worse it is, and your guarenteed NO PROFIT.

If they are afraid to give a materials payment up front, offer to accept it on the day you begin work.

Get a permit, if you don't get a permit (if required) you will have no legal standing to get paid.

If they don't want a permit or contract It's so they have power over you. This forces you to please them completly or risk not getting paid. Even if they pay you, it'll be for less then it should be.

Also concerning your first post.
"Telling me to get to work that he would have a check for the work we had already done, "
I think he was setting you up! It goes like this...you do some work, get a check but not in full. Then he keeps stringing you along. As long as he owes you you'll come running and do what ever he wants! When you're all done, the last check will never come. He will figure that you have been paid enough and make up excuses like "you took some of his wire"!!

Rick