I can't help you much on the Goldberg ARFs but you can do a search on those as well in the profile forums. Lots of people discussing them there but I'm gonna sound like a broken record here but go for a OMP plane. The OMP yak and edge both come out at 4lbs! I don't think the Goldberg stuff is really all their made out to be. I will agree on one thing though they both look great but I just haven't seen any videos of it really DOD doing all the high alpha stuff like the OMP profiles. Yes I am probably one of OMP's biggest fans and I'll admit it. Thing is just with the 5 planes I already got from them not a single one didn't do all the 3D stuff great.

On my little Yak I use a OS .50 SX with a APC 12.25X3.75Wide. It has bags of power and I fly at 5000feet above sea level. Now on my 46" Katana P kit (The one in my avitar) I use a OS .46 FX with the same prop and it's also a great match. I've now added the little .46 tower mufflers to the all the engines and the Katana loves the 500odd RPM more. It's a cheap and effective mod to do and worth it if you want a 3D animal. I am going to put another .46 FX in the OMP Boxxer I am currently building. I have yet to fly the Yak with the tower muffler so nothing to report there. Your engine will do the job just great as is too and well at a later stage you could consider dropping $15 odd and get a tower muffler for it. You should be able to swing a APC 12.25X3.75 wide prop on that motor easily. The prop you got there sounds fine though too. The AX is supposed to be a little more high performance than the old FX series so you are set in my eyes.