Alternatively, you can buy something like 2mm or 3mm dyneema and some length of 6 mm (hollow) swiftcord (open weave) and simply run the thinner line through the swiftcord. Stitch both lines together near the blocks and then massage the swiftcord tightly around this core and stitch the other end. Thus you'll end up with a thicker line in your hand as the hollow swiftcord now has a core thus resulting in a 8-10 mm thick sheet and it has a 2mm/3mm tail that runs throught the blocks. A large part of the friction through the blocks is associated with the thickness of the line and not so much with its weave. So you don't really have to strip the protecting outer braid from the dyneema line. This makes it alot less sensitive to UV degradating etc.