Not quite sure of the explanation you're looking for, but in my P40, the fuel and vent lines originate some 4-5" behind the wrap-around exhaust and the plug wire is routed back toward the firewall. Using a piece of dowel secured in the engine compartment I secure fuel line, vent line and plug wire to the dowel using zip ties.

As far as the primer bottle is concerned, it is simply a plastic bottle with a hole in the cap with fuel line attached. After filling tank and catching the overflow in bottle, I secure the top and use bottle to squeeze gas into the carb.