Casey,
Okay, you asked for my opinion, but don't say I didn't warn you.

Decathlons (and Citabrias) are a pure pain in the arse, so don't feel too bad about that one. Having a year and a half on a couple of different planes, tells me you'll likley do fine with the trainer, maybe even without a buddy box for the first flight or two, although that might still be a decent idea.

You're right to let the Spit wait though. Maybe a Super Sportster, Four Star (4*), or a Tiger 2 as a second plane this time around. All three are great flying planes.

The Spit might be best held onto until you're at least comfortable with the second plane, but being a top flight kit, it's a bit more "Sport" than "Scale" so it shouldn't be as difficult as a full out Scale warbird.

I think you'll do well. You're willing to listen to advice (opinions), and ask questions.

Enjoy!
Dennis-