Any taildragger with a fixed skid (or wheel) especially on grass or dirt surface will be more directionaly stabile on a T/O run but ground taxi will generally be more troublesome for most of the reasons mentioned above. The answer to the second part of your question is a free swiveling tailwheel will be far more unstable on a T/o run than a steering type.

Since this is the beginners forum I suggest when a taildragger type trainer is used that a steering type tailwheel generally works out the best to accomplish your goal. That is learning how to handle the aircraft in all phases of operation.

John