When I used Schaller straplocks, I would just take the Ibanez screw and grind down the head of the screw until it fit into the straplock
strap button.
You can also fill in the strap pin screw hole on the guitar then just use the screw that comes with the straplock.
The easiest thing to do is used Dunlop straplocks. Their screw is the "right" size.
