Well...not really knowing how the OP wants to fly it...
Just a WAG...but if he equips it with a battery that's large enough to give decent duration, and deliver strong power...the airplane might weigh perhaps 6 lbs. or more?
150W. / lb. would be approx 900W. soooo.....

I'm still flying the 2 airplanes I listed above with 3200 Kokam 4 cell packs, that I bought in '06...
They still deliver 55A. at WOT when fully charged to 16.8V. (no load...don't remember right off hand what the V. drops to under load, but I recall seeing between 700 and 750W. between the 2 motors ) but if I push things, my flight times are only about 5 or 6 minutes. max.
IIRC they weigh about 14 oz. (I'd have to check to be more accurate )

If I were to buy some new packs, I would choose something like between 4000 and 5000 mah. (and because of newer technology, they would be approx. the same wt. as the old 3200's )