ORIGINAL: Montague

2.5lbs on that amount of wing area is going to be a bit sluggish. SSC planes typically have more wing area and weigh about the same, giving a lighter wing loading.

You're going to need to experiment. I think the props I mentioned above might be good starting points, though it will take some testing.

If the engine wasn't the .15LA, but instead was a Magnum, OS CV-A, or Norvel, I'd say start with a 7x4 or 7x5 as those engines like to rev more than the LA does. The LA seems happier with larger props, so the 8x3 would be good to start with. All those props being Master Airscrews. Though I've been using the older MAS GF/2 line, I don't know if the GF/3 is going to be better or worse in that size. At least with the 8x3, the GF/2 is still easily available, since Master Airscrew keeps making them for us combat guys flying SSC. (The vast majority of Master Airscrew prop sales in that size are to combat pilots, and we buy a TON of props)