Sometimes a shot of fuel on the bearing will fix it. It's worked for me in the past but I don't know why.
You can coat and from what I've seen, it wouldn't be a bad idea to seal the inside of a ProBoat hull. Some epoxy will work just fine.
As far as gas boats, I love the nitro but I should have made the switch to gas years ago! So much less hassle. Set-it-and-forget-it needle settings, cheaper fuel even with me using Coleman camp stove fuel and Honda HP-2 oil and not having to pay big bucks replacing glow plugs constantly.
Clutches are available but to me it's one more thing to go wrong. I'm not out cruising past the bikini babes but running wide open so no need for one.
O, I've had a few props hit the bottom on launch, it really hurts when it's a high-dollar gas prop! You want to cry.....