I'm also learning with a tail dragger - a small .25-.30 size EPP model into which I've shoe-horned a .40! Hence, this has made it even trickier...
I've managed three take-offs in total, but each one has been preceeded by several ground loops, requiring at least a reset, if not a restart! The funny thing is that initially this thing wants to pull to the right, and only once it's up to speed does it then pull left (I think).
The wheels wobble quite a bit on the piano wire undercarriage, so I'm not sure whether it's got toe-in or out - probably a bit of both

The runway is very rough too.
My instructor's suggestion was also to start with some power - about 2/3 throttle, and that has helped. I guess it's just practice.