Hmm - I didn't notice yur needle settings in your last post. They actually seem a little on the lean side. Does it splutter a bit when it stops or just cut out ?
Get your HSN back to .25 in from flush. The HSN setting is very sensitive with the long needle carbs. Once you go just a little too far it will lean bog and start cutting out. Take the LSN back to 2.5 turns in from flush and see how that runs. Make sure idle gap is correct too.
Never worried too much with fuel tubing length. It will change your tune settings because of fuel pressure differences, but as long as you tune the motor to suit the length of tubing I don't think it will make much difference, but I don't know for sure. Is there an optimum length, anyone ??