I run my jib sheet through the crossbar, no bungees, just tied together. In the sailing position, unfurled, your crew needs to be able to adjust it from the wire. It easily slips through the crossbar so you only measure enough for adjustment from one side. A continuous line: 8 1/2 feet Boat width, call it 4 feet from end of crossbar to your hand, 6 feet from hand to cleat, 2 1/2 feet from cleat to cascade block and 2 1/2 back to other cleat, 2 feet to other end of crossbar and you have finished the loop. I use 3/32 spectra at the ends to tie these together.
The other sheet line, that runs on the pole goes from traveller car to clew of sail and back through a block on the traveller forward to a block near the bridle and back tied to the cascade block that the first sheet pulls on.
We use 1/4 inch on the hand held and 1/8 on the other.