Think it'll fly?

I would stay away from any 4 pitch props. That will lug the engine too much during maneuvering.  If you haven't been in the air in a long time,  a good  go to prop is a 6x3. The Skyray is pretty maneuverable when you want it to be. A 5x3 will offer very good performance over the 6x3 and typically faster. The engine is much happier when running fast but not over lean. Prop trimming is something I do a lot. You can really fine tune your performance doing so. The only real way to find out is to just try it as you might be surprised yourself.

             A 7x3 MA is out. It could be trimmed down to a 6x3 but it won't operate the same as a stock MA 6x3 due to the blade area being wider. It might work, it might not. That's a prop for a larger engine and it won't suit a .049. If your suggesting 15% nitro and a decent oil content of at least 20% your engine will be happy on that all day long.

         Loops in general are very easy on the engine as they require less demand on the engine opposed to other maneuvers. If outside loops are your thing, I wouldn't do them from the upright position. You will greatly lessen a crash if you enter the outside loop from the inverted position. The lazy 8's however are going to really taxi the engine when the plane is coming around from inverted into the outside loop. This is where the 3 pitch prop keeps the momentum driving. A 6x3 can even load the engine so dropping to a 5" is a good option.  Your plane is going uphill and it would rather pull the plane through as if it was in 2nd gear vs 3rd. Weight of model has a big impact here as well. Listen to your engine as sagging can result in rpm's.