Go with 1 continuous piece, if you can.
Several reasons for this.
1) If you need a rope or strap for an emergency--anything from a tourniquet or splint to lashing a broken paddle shaft-- you'll be better off with one long piece than three short ones.
2) When the long strap breaks you'll be able to salvage enough from it for two short straps.
3) I think it is easier to get good tension on the whole rig when you can adjust the single long strap from either end.

The beads keep the deck lines away from the skin. Put 2 on each line and move them a bit every time you think of it to avoid excess wear on the skin in that area. With a bit of air space between the deck lines and the deck you can ram a paddle in the gap and not tear up the deck.

PGJ