Drill oversize holes- fill with epoxy - how ?

[abl1111]

I want to oversize-drill several bolt holes through my transom ( under the water line ) to mount a swim platform. And, although I understand the theory of this, I want to brush up on how to properly, and completely fill these oversized holes w/ epoxy - so when cured I can drill through them w/ a smaller drill and mount my swim platform..

And, has anyone done what West System refers to in their manual w/ regard to epoxying a hole, and while wet, installing a bolt or screw in to assure maximum grip / water proof'ness ?

Thx