Check out his site

www.davepatrickmodels.com

He is VERY cautious about engines larger than 140 size. He tends to build very light, the firewall on mine appeared to be lite ply.

He advertises the plane to be around 10 1/2 pounds, but most people I know come in somewhat heavier, mine was 11 1/2 with a YS120. 12 pounds I think is a good guess.

I can't say about 3D as that is not my style of flying, but the 120 would hover it at about 2/3 throttle.