Regarding the line to a jerry can, I just have two lengths of diesel
rated hose. The intake hose has a weight on the end so it sinks to the bottom of the tank. The fuel
return has a double ended hose barb stuck into it. I just drop them in through the filler hole in the can.There is a bit of cord tied around the hoses so that I can tie them into the top of the can.
The can is tied to the boat's structure so it can't go walkabout.
The can is out of reach of spray or drips, so a plastic shopping
bag stuffed around the top suffices to keep it clean.
When not in use, the can is closed and the two hose ends are joined together via the hose barb to keep dirt and moisture out.
With this setup you can use any convenient can of diesel, or change from can to can as you wish.
I would only use this setup with diesel, definitely not with gasoline.
Sounds very rough and ready but has worked extremely well for many years as an emergency
See my earlier post as to how it all is plumbed.