I would use the .52 two stroke.
You do have to move the main gear forward, turning it around will not move it far enough. The drawing is how I did my Big Stik 60

I used a tail wheel assembly similar to http://www3.towerhobbies.com/cgi-bin...?&I=LXBN38&P=0 and ran a pushrod from the rudder servo to the steering arm on the tail wheel assembly. Adding a rear servo probably would have been easier. After you cut the hole in the bottom of the fuselage, glue small plywood doublers inside the fuselage to give the servo screws something to grab.