ORIGINAL: jooNorway
For pattern: 200-250Watt/kilo. 6lbs need 7-800 Watt. So you are right.
Rather a bit too much than lack of power.
200 Watts per pound. A 5 kilo (11 lb.) pattern plane needs about 2200 Watts. Of course the more the better as long as you keep the weight down.
Jim O