I have one of these partly built and am going electric with mine also. I am going to use a BP Hobbies 2915-5D motor on mine. I have been using this motor on a Super Sportster E and I have more then enough power and the motor seems to be running just as good now as when I got it. I normally fly at 1/2 throttle and only use full for take off and BIG loops. As cheap as these motors are, I can buy 3 of them for the price of 1 AXI and I don't see where there is any difference in power. Got about 100 flights on it now and loven every min of it. Why are you trying to lighten it up so much. The last one I built only weighed around 3 pounds and this motor will pull that fine. Get to light and you will be getting bounced around by the wind to much. I like your plane though. Lookin good.
Ed