Unless you are very confident in your take-off skills, I would be wary about switching to a taildragger. They are much harder to take off than a nose wheel plane. I switched and wished I would have waited a little longer to develop my skills a little more. I had to make a few repairs that I probably wouldn't have had to, due to blown taxi- to- take off mistakes.

As far as where to mount the main gear, you may be able to leave it where it is, depending on the plane. Mount your tailwheel and see how your plane balances.

Mike