Chris, try the Sika-flex 291/ 292 marine adhesive's / bedding compound. As you could tell the numbers will determine it's adhering power. Check the dates stamped on them. Sika flex is made by maybe the biggest paint manufacture in the world. They have done the research. It's a great product any bit as good as 3m or better. I used it for many many years with great results. 3 M seems to be pushed by the sales reps.???? in marine store, it  Also is a good product, but pricer. Something to remember caulking is not a bedding compound. The caulking sold in building supply stores is nothing the same as marine adhesive. Good luck on your repairs. Boats are time consuming to work on. Word to the wise. Take your time to do it right and in the long run its a project you won't have to worry about for a long long time if ever. When something get's real frustrating stop and go work on something easier and then go back and do that till it's completed. Save on a lot of pain and mental anguish. Unless your a masochist or a contortionist. Like most of us. 

By the way I have been to Alaska many times by boat when I was in the merchant marines in my day. We used to bring supplies up to, if i remember correctly, Juneau, Skagway, ketchikan. this was back in late 60s to mid 70s. We would leave Vancouver BC. in January in some of the worst winter storm in the north pacific. One storm to recall this was brewing for a week. We tied up for three day's in a cove hoping it would subside. We had to to move on to much money being tied up. When we hit the open pacific unbelievable. Visibility was to the bow only. No Sat-nav, Chart-plotters, Gps, just radar and charts. After a day winds calmed down. But after a week of gale force winds the fetch created 80 foot swells. We had 120 ft. massive tug with two 1,800 hp. Diesels. We were getting 3 knts. plus towing 50,000 ton barge's. The water line to the top of the chimney stack was around 65' and we were being buried. Some day's I wonder that I'm still here.

Like Gordon Lightfoot said:  Does anyone know were the love of God goes, When the big sea's turns minutes to hours.

Lawrence, May the wind always be in your sails.

To update this thread......    I finally got a sunny day to pull off a section of my rubrail.  It was rotten at one side so I was going to pull it anyway.  Turns out those screws that  I thought were the rubrail screws were not.  The rubrail is screwed into the hull, behind it, countersunk and filled with the remnants of dophinte are the extra long screws.  Their only purpose seems to be to attach a mahogany strip  for the headliner to attach to.  I am thinking about my next move.  Most likely it will be to remove those screws and fill the holes.  I am almost to the headliner in my Vbirth remodel, I think it will show me what I need to do before I actually fill those holes.  

Slow and steady

Chris