I am going through this same issue right now. The boat I just bought has no righting line (What is that about?) so I am trying to decide what is best. Back in the late 70's some guys in our fleet came up with their own "Hawaiian" system. The advantage of this system is that it can be used to hold onto when trapped out.

We used old mainsheet with a bowline on both ends. It was tied with smaller cord to deck just at the transom. The other end stopped at the front pylon. In between, at 18" intervals a knot was tied. The pylon end was attached to shock cord that looped around a couple of blocks.

When I resurrected this system back in about 1994, I had a hard time getting the tension on the shock cord right, so I used a figure eight to "Stop" the rightline from going out. This knot was between the shcok cord and the small eylet riveted to the front pylon.

All of that being said, my new(relative term) boat has no eyelet on the pylon and no hole drilled in the deck at the transom.....

This sort of thing worked great, but I am considering buying the hawaiin rig in the catalog, rather than trying to reinvent the wheel. I prefer this type of system to the single righting line or the mainsheet/ dolphin striker bar. I tried that just before I went back to the hawaiin system in 94.....I kept loosing the end of the rope through the trap lacing and it never would stay where you put it. But it DOES work and works well to right the boat.