I had a customer who had similar problems. He was 6'7" and 270lbs and developmentally disabled, he was getting flats every week for a variety of reasons. Sometimes he didn't have the correct pressure, sometimes he ran something over and he had a hard time remembering to put air in the tires. We tried better rim strips, tire liners, slime tubes, thorn resistant tubes, and took the time to try to teach him how to properly air up his tires...none of it worked so we finally got solid tire inserts, now we only see him when the tire tread wears out or he breaks something. He only uses the bike to get to work and back and to his flag football games and he says he doesn't feel a difference in how they feel he (and his mother) are just happy they don't have to worry about flats. I think one of the solid tire inserts might be the best solution in this case.