My comment on the 2 planes you chose:

They are different animals. I have the Freestyle and seen the Flip fly several times. The Flip is made for 3D, the Freestyle is kinda like a 3D/Pattern flyer (read not for extreme 3D, but not far behind). Both are easier to fly than a scale plane would be. The flip is a booger to land on a windy day.

Its hard to put into words, but to me, neither plane flies 3D like a scale plane. The Flip literally "flips and bounces" around the sky, while the Freestyle flies a little smoother (in between a flip and a scale flyer), then there's the scale plane, even smoother flying.

As for the engine, if its similar to the ys 63 or saito 72 in size, power, and weight, then it will be fine on either plane.

Also, there are some 40 sized scale planes around. You may want to post in the 3D forum (or search). I have read about a 40 sized cap232, extra 300, and I believe there is a new Giles 202.