I'm not terribly familiar with the 6.0 (or the boomless sail) but on my 5.2 I leave the traveler car about 3 inches from the end of the traveler and sheet 'snuggly' - definitely not firm, definitley not sloppy.
I find that the jib shape is better with the barber hauler exposed about 3 to 4 inches. I start by trimming the jib, barberhaulers engaged, until the tell tales are flowing steadily with the apparent wind at 90 degrees. This usually puts the leading edge, at the forestay, about 90 degrees to the boat, pointing straight into the wind. Even so, I still find it necessary to sheet firmly on the jib downwind with the additional angle introduced by the barber haul. Now adjust your barber hauler (and sheeting everytime you make a change) so that the top and bottom jib tell tales break evenly with changes in wind angle - your jib is now at full power. Then check that the main sail's lower tell tales are flowing (usually no problem at this point) but adjust the sheet to control the twist at the top so that the top is flowing and breaking at the same time as the bottom - it will have to twist some because the jib helps the flow of air around the bottom of the main.
Check now that by steering the boat up and down that all the tell tales are breaking evenly - you'll feel it when you get it right because the boat will just feel 'alive'. I also find, and this may be very specific to the 5.2, that by zigging slightly downwind, I can get the boat to drive faster and lower but don't ever, ever, ever let those leeward tell tales break. Once you've found these settings, remember them (or mark them on the sheets) and you'll find a quick reference for getting the settings close next time you round the B mark.