Hi I wanted to get my new (used) ride a 10 foot Brown Dog slider wet yesterday but when I put the fin (that came with it) in and tried to tighten the retainer screw (that came with it), it just wouldn't tighten. Inspection showed the plate was flush to the base of the fin, but the plate slid up and down in the slot the plate slides along, which is wider than the thickness of the plate. Rummaged around and found a retainer set with a thicker plate (as thick as I've seen or used in any longboard finbox), tried that but same outcome... Is the solution a thicker plate (presumably so thick that it can just slide along the slot but is effectively flush when tightened)? Or are there fin boxes out there that need you to say use a washer above the fin box (extending over the gap in the fin box) to pull the plate up against. I probably haven't explained it very well! Surprised that I haven't came across this before. Looked at my other fin set ups and there isn't any overlap in the screw head over the finbox gap so the plate must be pretty much flush in the slot...