In my head, I see this as a body of water with small patches of land here and there, so a lay-up zone is not possible.
Based on that, I would prefer ratcheting drop zones. Miss from one, move up to the next shorter. That's not based on scoring spread analysis, it's just how I would like to play it.
I don't like the complication of a counter-loop-escape-box in the flow chart of how to play the hole. Throw two, then go to the next drop zone, for example. If the rules change based on the number of throws you already made, that's too complicated for me.
The penalty throw for missing the island is punishment, as is the loss of the disc underwater. Making them do it over again is more - and in my view, too much - punishment.
Also, if you play it as "go to the next tee if you miss" then all the players are basically playing the hole the same way, except that the players that start from the white tee get a little head start.
One more note, not everyone can throw accurately 90 feet. For example, if you had all the female PDGA members play, 27% would miss a 75 foot wide island on the other side of a 90 foot water carry. (Most of the misses would be left, right, or beyond.)
So, if you still have a forced 90 foot carry over water from the weenie tee, make yet another drop zone on the island.
And still give everyone the option to concede OB without pointlessly tossing a disc into the water. They can advance to whatever tee they want to play from for the appropriate amount of +2's.