You could do with the wires if you act to keep the plane light...

e.g. Maybe a 2C engine or something like a Saito ( which are very light ) 4C, and throw the batteries on the mount to get the C.G. right.

Don't go overboard on the battery size as well ( I know I do ).

If you get it to come in around 9-10 lbs they will work, but harden the mounting area as much as possible too.

Mine came in much heavier ( around 13-15lbs ) but I went with struts, scale changes, etc... as were suggested in the rather huge CMP Hellcat thread on the Warbirds forum.