Nevermind, I found my answer. See that unopened post? The tip has to be cut off and its a heck of a measurement. According to the BEMM it has to be cut at 19.64mm +/- 0.12mm, think i got it at right about 19.73mm.
It seems difficult to find a clear cut answer on the best method of connecting the auxiliary fuel port to the Espar fuel line. As far as I can tell the auxiliary port MAY require a 5/16 OD fuel line, and the standard Espar fuel line is 4mm OD and 2mm ID (thought they make a black 6mm OD version as well). Espar makes an "adaptor for fuel pipes" with 7.5 and 3.5 mm ports they sounds like it would accept such hoses but it seems to be vaporware. Anyone have clearcut guidance on the best products for mating this all together?