I'm not familiar with your engine, but using a 6.4 (105cc) Brison twin weighing in at 5 pounds my Giles came in a little heavy. Using a lighter 70-80cc single would have dropped the all up weight by about a pound or so improving performance that much more. I'm sure that your 70 will fly the plane, but consider doing everything else you can to offset the weight of a heavier engine. Go as light as you can everywhere else.

Consider placing a single rudder servo in the tail to help with the C/G, and move the battery back forward. The best C/G for this plane works out to be at the center of the wing tube, not in front of it. I ended up installing one of my flight batteries just aft of the top hatch under the turtle deck.