A Dremel tool with sanding drum makes short work of enlarging the cut-outs to fit a larger prop.

You used a FILE? Jeez; no wonder you're aggravated. That would take forever.

BTW, I would stay with DuBro. Now that Goldberg stuff is difficult to come by, the DuBro is the best plastic spinner available IMO. Stay away from the SIG on a powerful four-stroke. SIG spinner faces are held only by the two screws; these won't take the torque of a powerful four stroke. The Dubro, like the Goldberg, has four stout pins in addition to the 6-32 bolts/locknuts. Plus, you don't need a hammer to install it or a pry bar to get the face off, like you do with the Goldberg.

My pal broke a SIG plastic spinner on a YS 63, and I broke one on a YS 91; just by advancing the throttle.

Steve