Pay RE attorney up front fee/retainer?

[Michael G.]

My attorney is asking for an up front fee or a retainer to be applied toward closing my short sale/wholesale deals. He's investor friendly and understands creative REI so I hoped he would take his fee on the back-end. I even offered that he raise his fee in return for getting paid on the back end. Also, when doing a double closing is the attorney fee per contract? So if he charges $500 for a normal closing is it $1000 for a double closing? Has anyone had experience with this?