RE: What to choose for 2 Stroke Engine, RPM or Thrust??
The 10x7 will give you higher top speed (power) and possibly land faster. If you want to go the opposite way with greater static thrust, shorter takeoff, more vertical, slower landings, I would even try a 12x4 (assuming you have ground clearance). It might make flying more fun for you, especially if you are new at flying.