the Pitts is not suitable as a training aircraft for tailwheel endorsements.
I did mine on the Pitts and I know others that have too. One thing I would say though is that the Pitts isn't really suitable for standard tailwheel training because it is a non-standard technique type. I wouldn't advise anyone to do tailwheel training on it unless it is the aircraft you want to fly/own.
I wasn't taught wheeler landings because it is tougher to get right than three-pointing in the Pitts. The CAA flight manual supplement recommends three-pointing as well.