Having gone through a complete topsides re-bedding in the last year on my C&C
24, I would strongly recommend you consider using Butyl Tape instead of the tube-based sealants.
Not only will the process be simpler and less messy, but you will likely have a much better overall seal of potential leak areas. And, I believe you willl find that the cost is less as well. You can get the proper width tape from a variety of sources; I got 4 rolls over at Amazon.com
for a good price
There is a very good thread over on SailNet that examines the whole thing in detail. Bedding Deck Hardware With Butyl Tape - SailNet Community