Weight was the only thing I could think of that would make GP recommend a 1.20 for a plane about the same size as the US, except maybe the fact that the same distributor also sells the OS 1.20.

I've looked pretty hard at the Big Stik myself. I'm still on my trainer and hope to be ready to try a 'second plane' this summer. I've seen the US60 fly and like it but I really like the looks of the Big Stik better.