I have the Toyo810G which is 2 lbs lighter (17 vs 19) than the newer GII – it doesn’t have the fancy knobs that the GII has – and have found no problems with attaching a 360mm Schneider Symmar-S which weighs 1545 gms (3.4 lbs). Of course the camera requires a substantial tripod and head – mine is a Series 5 Gitzo and head. It does collapse without the rail attached but still occupies a rather large diameter which may or may not fit under the seat or in the overhead.