Attaching new bindings to old board

I recently bought a 2002 Hyperlite Premier 140 on FB market, but the bindings are too small for me, so I bought a new pair of Obrien Clutch bindings. The new bindings have M6 screws and I believe the board takes 1/4" screws. I can't seem to find any 1/4" screws that match up well. The M6 screws that came with the binding have a little rim that fits into the bindings to keep them from twisting. Please help, rookie wakeboarder here.