Henry,
Sorry to hear about your heart problem. I sincerely hope that all is going well for you. When I had a stint placed the FAA would not accept any reapplication for a Third Class Medical for at least six months. It take the medical branch in OKC at least three months to process a request for special issuance. I was without an medical for about one year. Now I have to have a very through annual inspection to keep my medical.
For goodness sake talk money with your broker before any sales transaction; it may save you a lot of grief in the future.
Although I am not a broker I have sold a few planes for other folks. We always agreed upon a fee at the outset. I charged a larger percentage for a low cost airplane because the time and effort is about the same (maybe more) to sell a 150, Cherokee, Pacer or the like as a 310 or 414. Low cost airplanes will likely be sold to first time buyers and they can be a real pain. I did the low cost planes for 10% and 5% and 6% for the higher value planes.
Good luck to you and keep walking.