If you really like slow fix then Japanese brand Advanced Technology AD-4C adjustable harnesslines are great, except it is very very very tight to get the boom thru the harness loops when using North Sails Platinum booms as those booms are pretty fat. But those ones are nice, as you can easily change the lines if they wear out one day and their V-shaped cleat is super - it wont ever slip! But I use new (yellow ones - the orage ones were horrible - all orange ones were slipping all the time) Point-7 Vario harness lines. They are quick fix type and they wont slip any either! And P7 has lines every 2" separation i.e. 22-28, 24-30, 26-32, 28-34, 30-36....
Advanced Technology:
www.atltd.jp/items/gt_3.htmlPoint-7:
point-7.com/