In my opinion as a tailwheel instructor on Tiger Moths, it will save you £££'s of money in the long run if you have a reasonable understanding of tailwheel principles before flying the Tiger Moth. Bashing around the circuit in an aeroplane that will cost you twice the going rate of a Cub is not recommended for the bank balance, or indeed very good for the aeroplane. Understand the basics and you will be well prepared for the Tiger Moth, or indeed any tailwheel aeroplane afterwards..
As Warped Factor says, after 20ish hours of Cub/Chipmunk etc, you won't have much of a problem converting to the Tiger. Lets face it, it's not that difficult, just different (and colder in winter

)! After all, its definately 1920s technology, and handles just like a 1920s aeroplane.
As for the '5hr tailwheel course', I have only ever sent a guy off solo in a Cub from scratch with less than 5 hrs on tailwheels once. He was a natural pilot, who took something like 1:30hrs and off he went. Swine!!
The '5hr tailwheel course' should be re-named the '5hr preparatory course', 'cos it only just scratches the surface for most nosewheel pilots
Warped Factor, we obviously know each other; I may have even sent you off solo!