It's a fairly cheap/basic/generic MTB rack but is easily wide enough for the seatstays.
The nearside stay attaches on the outside of the seatstay - the farside stay attaches on the INSIDE of the seatstay. This keeps the rack centered.
I had to cut the vertical rack stays to get the rack a bit lower. They normally have three holes for adjusting the height. I made my cut just above the bottom hole, then added another hole much higher. I had to cut the piece of rod that fits inside the stay too, by about the same amount.
Rather than attaching to the upper rack mounts on the 907, I used a Giant rack-mount seat-clamp. This makes the routing of the top stays a bit less tortuous. This may not be a problem on larger frames (mine is a medium) as the upper rack mounts will be a little higher.
I've extended the usefulness of the rack as a fender/mudguard by using an old RRP neoprene fork fender at the front and a cut-off section of a frame-mount (crudguard-style) fender at the rear.