First things first - welcome to the Forum! I think you'll find it a fun and useful place. It's inhabited by some decidedly odd people, but most of us are relatively harmless.
I've never worked with fiberglass hulls or laser-cut brass railings, but I imagine the latter are similar to photo-etched brass parts. If so, the two adhesives that come to mind are epoxy and cyano-acrylate (otherwise known as "superglue"). Both come in several varieties, with different viscosities and drying times. I imagine you'll be drilling holes in the deck and plugging the rail stanchions into them. If the underside of the deck in question isn't going to be visible, I'd think a blob of stiff, slow-drying epoxy resin on the bottom would hold the stanchion in for the rest of our lifetime. If the underside of the deck is going to be visible, I guess the approach would depend on how thick the decking material is. Trial and error should establish whether the stanchions will have a tendency to wobble. If not, a drop of medium-fast-drying CA should do the job. If they do tend to wobble, you may have to figure out some means of supporting them.
I'm only able to talk in extreme generalities here, because I've never done a project like this. I suspect some Forum members who've got experience in RC models will be able to help more intelligently.
Good luck.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.