I want to throw in another idea. Tip weight is very important. Engine offset and rudder offset are actually bandaids to a problem that has a very easy solution. You need to always make sure that your lead out exit point is in the proper location. let your plane hang by the front lead out and look to see how the fuselage is in relation to the ground. It should be parallel or slightly nose down. If the nose is even slightly up then you have a problem. The L.O. location should always be close to the C.G. and never forward of it. I am a C.L. combat pilot and I use no engine offset and do not even have vertical area. We gain Line tension from Lead out rake.
The tip weight is there to offset the weight of the lines. If .015 steel was used that was your problem most likely. You needed to use .012 steel. I would not recomend going smaller. Keep the lead out rake in mind with all of your future planes and they should hang out there just fine.

Well I’ll through in my two cents. I’m old combat flyer from the 60’s and still have 2 Ringmasters with Super Tiger 35C’s and a newer Flight Streak ARF with a REAL FOX 35C (not the new one with the cheesy muffler). One thing that has not been mentioned is the line lead-out angle from the bell-crank. If the lead-outs are parallel with the leading edge the engine has a tendency to point into the center of the circle. You see the at launch the wing is not flying yet and the outboard counterweight and the thrust line of the engine as well as the line lead-out angle helps to point the engine to the outside of the circle. The rudder will have no effect up to the point the wing is flying. 1\2A is tuff to launch as there are not many horses and the wing loading is generally high. With all of the Wizards (a plank wing aircraft) I have taught C\L with to all the kids in the neighborhood, the launch resembles dragging the airplane on the end of the lines (in air) until airspeed is attained. Don’t forget to check for wing twist especially if the model is finished with an iron-on product. So if all the above posts have unearthed no solution, check the lead-out angle and be ready to take that big step backward on the release of the model. A bit of a push on the part of the person launching is necessary too.