Paul

Just a plain tube will suck a bubble straight down the hole! The felt type breaks these up, holds a certain amount of fuel and maintains the supply.
I now only use MAP (Canada) bubble traps, same all the people around me, plus we use the Hi Flow felt clunks we sell, no air in the hoppers and just about 100% success always. People discus flame out issues after they are highlighted like in this thread, my lot just shrug as they follow a path and don't change from it. Obviously building a tight fuel system is critical, but we don't suffer with flame outs in my group.
Just keep an eye on your pump voltages, this now will give you a fuel system health check, we only use premium paraffin and we don't suffer algae like Jet A1 users.

Glad you are sorted

Dave