What Matt said. Just use a clevis pin / ring ding on the lower block. Open the ears of the traveler.

As for the top, Hobie sells (or at least used to sell) shackles that come with a quick-release pin that is held on with a captive wire. There is a second pin the runs through the shackle to keep it attached to the boom. Basically, all you do is install the shackle once on the boom, then each time you rig the boat, you use the quickie pin to attach the top block.

One of the best features of this system is that you can get the blocks off the boom very quickly when you hit the beach. Depending on the wind and water conditions, this can be a lifesaver (figuratively speaking).

I've been using this setup since 1997. I have never seen or heard of one of these failing.

And don't forget, ALWAYS tape ALL of your ring dings.

Hope this helps.

Mike