Nope, I'm on a straight line to the engine in most cases. As the engine starts I open the valve one or two clicks. Once I hear the engine start switching to Kero, I close the valve.

From the engine is a the three MM line, then at the canopy I have a 3mm to 4mm connection with a check valve.

I use the check to connect my propane.

Then when done I just lay the line inside the fuse.

And go fly.

Been doing it for over 150 starts now. Smooth as silk. I love it cause if there ever is a problem, I can shut off the fuel source right away. Immediately.

I consider it a very good safety measure.

You can run the propane through the normal tank onboard and the normal propane solenoid, and just feed propane from off board. That works too. I read what matt said, I have not had any vapor pressure issues in 110 degree texas heat. Don't think you will either.