The gas leaking from your float bowl and the gas leaking from the jet at the bottom sound like two different problems. I was blessed with a carb with a good float and needle valve, so I can't help you there, but I do have some experience with the leaking jet. There is no gasket or anything between the brass jet and the bottom of the carb; Gurtner just relied on the harder brass jet mashing into the softer metal of the carb body and forming a good seal. It works once or twice, but after you take it apart a couple of times it doesn't seal so well. I just wrapped the base of the jet several times with teflon tape (taking care not to cover the inlet holes) until the leaking stopped.