South Coast 26'.have dock damage hole thru deck at rolled over edge of deck. hole is 2 1/2" x8" long.limited access from cabin below for repair.have molded piece of fiberglass to waxed undamaged portion to establish general profile and released it .plan to prep inside of hole to fit moulded piece to use as a backer.basic profile is a Z with top of Z being deck, vertical of Z being rollover, and bottom lapping over hull. it will be difficult to mate and bond prepped piece to prepped spot inside with resin to insure a good bond.would MarineTex putty be a good cantidate for securing this fabricated backer,or should i shoot for pure polyvinyl using same material throughout,and bustin my knuckles to make a smooth flat patch?