Yep, RP knot on the boat because it's quick and easy. FG knot at home because it's stronger and thinner so it doesn't get hung up in the guides, but takes longer and is more difficult to tie.
If you are having trouble with the FG knot, watch this:
It's true that the FG is harder to tie than an RP but it's not that much harder, I'm no genius and I have tied hundreds of FG knots.
And it is finished with a risotto knot which is the same thing you finish your serve with when using hollow core.
So far, in ~8 years of ocean fishing, I've never needed to ti top shot to braid on the boat. I always have a backup rod, so if something fails, I switch to that and sort stuff out at home.
Under no circumstances would I use an RP knot for bigeye or bluefin. Why? We routinely push the drag up to 35 pounds to stop the big runs. It's that or get spooled. My testing shows that the RP will cut through the mono somewhere between 35 and 40 pounds. I've done multiple tests, it's aways there. With 35 pounds of drag, you are dangerously close to the cut off zone.
As for your earlier suggestion of using fluoro, I don't want that. The mono is there because it stretches and that takes some of the strike shock, head shake shocks away. I _need_ the mono.
I have friends who swear by the RP. They also have only caught small tuna down in San Diego, they haven't gotten into fish in the 150-300 pound range.
All that said, people can do whatever they want. I'm pretty strongly opinionated because all my bluefin stuff came apart 3 years ago. So I spent a bunch of time testing everything to 70 pounds on a scale. RP knot didn't come close to being strong enough.
Palomar is the strongest terminal knot, it's a 100% knot, never breaks in the not. But hard for me to tie.
Springer is not as strong as Palomar but it is much easier to tie, you just need at least a 5/8" tag.
FG knot for braid to mono, properly cinched down (the braid gets shiny and feels hard like plastic), it's up to the tuna challenge.
RP I just never use after observing how it fails.
