I don't agree that the UCD is not a good 3D trainer.

I had a Modeltech Magic as my second plane. Ugly, yep. It flew pretty well but was somewhat limited.

If you're very confident in your trainer I believe you could fly the UCD well. Just start on low rates. Low rates will be much more responsive and twitchy than your trainer ever could be and flipping it to high rates lets you tumble and toss it in any direction at well. I have the .46 with a Saito .91 and I absolutely love it. It will do any 3D maneuver in the book, except harriers have a lot of wing rock and I needed to mix out the nasty coupling in knife-edge flight.