Hey, Duane...
The gasoline line is an idea I came up with about 3 years ago, when I routed it in gasoline hose, but had some difficulty with, so I dropped the idea for a while. About a year ago, I worked it out, when I went to metal tubing, so I re- implemented it.
The idea is that the gasoline hookup is actually at the rear of the system, next to the wall. So there is no need to "fish" a hose under the van, which makes installs simpler. The actual gas hose, between the tank and system, is about 2 feet long...
That tube (and all of them, now), is 5/16", not 1/4". So is the pickup tube that is used to tap the tank, and the hose between the metal tube and the fuel filter of the Kohler. Since we changed to that, there has been no need for a fuel pump on any of the systems that have it. (I got the idea from my focus on airflow in the system, and thought that the principle should apply to fuel supply as well... and it did.... kinda like Greenie's 2.5" hose idea... larger hose = less resistance...)
That means one less thing to go wrong, and no fire hazard potential from a fuel pump "feeding" a fire of any kind. The Kohler fuel pumps have enough power to pull through that tube, from a gas tank. We haven't installed a system with a fuel pump in a couple of years, now...