I am happy to report that my repair was a success. I bought yellow 1/4" tygon fuel line that can be submersed in fuel. My local autoparts store sells this line mostly to snowmobile enthusiasts.
I posted my repair in the Tutorials section:
Removing and refitting the gas tank filler cap (2000 M900 ie)As for whether the lines should be there or not. In my experience, when the bike was on its side stand, the fuel would pour on the rear header causing a sizzling sound. Had my bike been really hot (I started and rode to the gas station first and it was about 45 degrees) it could have been a different and sad story. I added another line for the gas tank vent instead of a "T" for troubleshooting purposes.