In converting any airplane to a conventional gear (taildragger) from a tri gear will not substancially alter in flight chacteristics but of course will change ground handleing and takeoff, landing behavior.

Your main concern in the conversion as you indicated is the fore and aft main gear positioning and the old rule of thumb is put it at the leading edge of the wing. While this usually works to one degree or another but due to differant wing designs (aspect ratio) that 'rule of thumb is not alway optimum.

Just keep two points in mind. Given the fact with conventional gear must have the mains ahead of the CG, If the gear is too far forward the airplane will have a tendency to bounce on landing and be more directionally unstable on takeoff and landing after touchdown. Now if the gear is too far back the airplane will be far more directionally stable and less tendency to bounce on landing but will have more of a tendency to nose over both on takeoff and after landing particularly if up elevator is not held during the initial takeoff run or after landing.

What I would do is If that airplane has a raingutter fuselage I would make a set of holes for the gear just slightly behind the leading edge and another set perhaps three quarter of an inch just behing that (its a very simple to change with that kind of fuselage. Then just fly and change if neccessary (the old cut and try technique).

Another factor with taildraggers is if when setting on the ground
the airplane has a very steep deck angle this will make for poor ground handleing and a difficult take off. Many time the simple expediant just putting a spacer block between the fuse bottom and the tailwheel bracket or extending the the vertical portion of the axle wire to reduce deck angle. Many times this will dramatically improve ground handleing but do keep in mind propellor ground clearance.

John