I almost bought some of those on Tuesday. Did you sandwich the nuts between the two pieces of ply in your bases, or put them between the deck and the base? If they were on the bottom of the base, how did you keep the bolts from bottoming out into the deck as you tightened them. I had some concerns that the bolts would only be threaded into the 1/4” or so at the bottom of the ply and push down against the deck and up against the base as they were tightened. I wanted an inch or more of shank length but 1/4” was the longest shank t-nut I could find. If they’ve worked for you all these years though, I’ll probably give them a try.
I thought about using those for the bilge panel too, but they would be installed backwards and probably pull out of the fiberglass. Will they even work in straight fiberglass without any wood?