Another option is to install deck rails and you can slide seats in and out and change position as much as you want.
Scotseats sell a system but it isn't cheap, maybe old bus system would be worth looking at?
Failing that, deck inserts are worth a look as you can seal them up relatively easy (I would epoxy them in flush) and will provide a glued and mechanical bond. You better be sure your deck is solid before going this route and I would use maybe 8-10 fasteners per single jockey seat.
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