Whatever caulking compound you use, don't tighten the fasteners down completely right away. Tighten the fasteners down nearly all the way, clean up the goop that squeezed out then let the stuff set up to create a gasket. Go back the next day or so and harden the fasteners down.
I can't believe people are still advising a two step tightening! I'm sorry but it's just, old, outdated and poor advice for 98% of DIYer's!
To properly execute a two step tightening you need to know the exact condition of cure and that's nearly impossible due to temp and humidity differences. If it's to dry, and past prime tightening time, you'll likely break the seal between the bolt and the sealant by twisting it. This break between bolt and sealant will allow water ingress. If it's still to wet, the curing sealant, then what's the point? To get this two step process "just right", as in, not to hard not to wet, is nearly impossible especially for those who don't fully understand cure characteristics of the individual sealants available.
I learned a long time ago, from the masters at Hinckley Co., how to properly bed and it DOES NOT include a two step process no matter what Don Casey says.
My boat yard laughs at this "two step" method/wives tale/urban legend, all the way to the bank..!! I was just talking with them last week about a deck job they did at a cost of 28K. The owner used a two step process and broke the seal at over 80% of the fasteners on deck.. The boat had been surveyed at about 95% dry four years before he then decided to re-bed.... 28k later... Need I say more?
Unless you can guarantee that you will absolutely, positively, 100% NOT budge that bolt during the 2nd stage of tightening, after a period of cure, DO NOT use the two step process! I'm convinced this is, or was, a process created by boatyards and industry insiders like Don Casey, and such, for future industry revenues of deck repair. It is my guess that the majority of wet decks are caused by poor bedding techniques, including, but not limited to, the "two step"..
Countersinking, is and a full tightening, is enough trust me!!! In over 18 years of using the bevel/countersink and single step tighten method I have NEVER once had a re-leak. When I say this I use the photos bellow as evidence to support eh bevel/countersink and one step tighten method. Oh, and I've also NOT used 5200 in those 18 years either.. That's another wives tale for another day and thread though...
The pad eye bellow was installed on my AB RIB using the countersink/bevel method with an immediate and full tightening and "squeeze out" as some call it. It is now 6 or 7 years old and has NEVER, EVER leaked even one drop of water! The big clincher here is that these fittings are BELLOW THE WATERLINE
and are used to lift my RIB into the davits so they do see stress and full immersion bellow water
something your stanchions or genoa tracks certainly will NEVER see for more than a few seconds or so.....
P.S. My thru-hulls are also installed with a single step tightening and I've also never had one I've installed leak and I've installed LOTS of underwater fittings having worked in a boat yard in my younger days....