I am installing the custom sliding seat and rigger to an Annapolis Wherry. The wherry I built has an inwale on the interior of the frame, so I cannot install the mounting block(s) to the interior side of the boat as shown for the Oxford Wherry. I am thinking that I will fill in one of the "gaps" between the inwale and the side of the boat, and then build a mounting block that will sit on top of the outwale/boat side/spacer block/ inwale surface. Does this seem like it will be strong to withstand the full force of every rowing stroke?