If the fore and aft positioning of the headsail car does not allow adequate adjustment—perhaps owing to constraints on its track location—a barber hauler can be used to pull the jib sheet inboard, outboard, or downward. Named for the Barber brothers who first used it when racing, the barber hauler is a loose piece of gear that attaches to the sheet with a ring or snatch block at one end and to a winch or convenient hard point on the deck at the other end. It requires the jib sheet to be rigged inboard of the shrouds, and it is therefore most useful when sailing close hauled.
While beating upwind in more than light air, hauling the sheet inboard until the jib is right on the verge of backwinding the main will often let the boat point higher and will also reduce heeling.
When falling off from close hauled to a reach, ease the jib sheet slightly and haul it outboard, toward the toerail, until the jib has even curl along its luff and its leech is not hooking to windward or flogging.
Fine tune the combination of sheet and barber hauler, using the sheet to adjust tension and the hauler to adjust angle.
Some boats have a barber hauler permanently rigged and can then dispense with the jib turning block car and track. This unclutters the deck and removes a tripping hazard, especially when barefoot.
To experiment on your boat, make a simple barber hauler from a sturdy carabiner and a length of line. Hook the carabiner onto the jib sheet and run the line to any convenient point where it can be made fast, ideally on the windward toerail.