Couple of questions: 1: What's the budget? 2: How often do you want to repeat this exercise? My recommendation would be to sand-blast all the bolted metal-to-metal joints right down to bare metal, then weld all joints closed with a wire-feed welder. This only leaves the wood-to-metal joints around the now non-operational slit, which would be addressed with flashing, as Kim suggested, and the best sealant the club can afford. Re-seal and repaint the whole thing afterwards. Probably a three-or-four weekend operation, start to finish, depending on number of helpers. Having helped assemble the dome in it's original configuration, pre-Refractor House, I am familiar with it's construction and think that while welding most of the seams closed would be a bit time-consuming (the prep work, mostly), it's a one-time deal at the most long-lasting, at least for our lifetimes. There are also now some specialized manufacturing epoxies that would last for up to ten years before de-bonding to metal, but those are expensive and require proper prep, as well. I'm sticking with the welding option for best bang-for-the buck, and long-term stability.