FWIW - re doing training on tailwheel - we do a majority of ab-initio training on tailwheel and have for many years. On average, students take an hour or two longer to get solo (compared to nose wheel) but progress after that at the same rate and end up with the same number of hours in their log books as those we do nose wheel (again on average).
Typically we move them to nose wheel for nav training and they normally quickly adapt to the nose wheel without drama.
Going from a nose wheel to TW, usually on average, takes longer and can be more frustrating, particularly if they have learnt on an easy to land aircraft that has let them get away with being a bit sloppy in landing attitudes and approach control.
If you learn tailwheel from the start you don't know any different. It should take about the same number of hours.