Elvstrom-style bailers work pretty well (better, I think, then the plastic Sunfish bailers), but can be a pain to step on with bare feet. If the boat is slid over beach/grass/dock/trailer bunk/whatever they're prone to damage if not securely closed.
Right now, I just use a quick release, expanding rubber plug in my Despersia, and it works SO much better than unscrewing the Despersia cap, with the water trying to drain thru the holes in the Despersia threads...not to mention potentially losing the cap if I unscrew it all the way. My rubber plug quickly yanks out and stuffs back in and is on a lanyard, so it can't go overboard. I have a Puffer and just drilled a hole, using the same type of rubber plug and it works great. No bailer at all, but just the hole and plug. The Elvstrom or Anderson type bailer WOULD have to be out of the way....like near a cockpit wall, etc??. Fully retracted, they shouldn't get damaged, loading the fish on a trailer, etc.
Any rate, I know lots of different dingy style sailboats use them, but have never seen one on a Sunfish. They are pricey if buying new, but if the work better.....?
oh,....yeah.… I use the same type of plug on a transom drain too. Works great for that "errant" water that is coming in from somewhere, when bashing about in heavy waves ;-)
Boy, I think I'd just stick with your current expando plug in the DePersia. The Elvstrom needs a fair-sized hole in a pretty flat part of the hull that's also out of the way, but still convenient to reach--bit of a PITA all the way around in the small Sunfish cockpit. If used a lot the gaskets start to leak & need replacement. The metal thru-the-hull DePersia part has to be less damage prone than an Elvstrom. Elvstroms are a little pricey--how'd you end up with extras?
I bought the pair off Ebay for $12 shipped. Thought I might use one one on my Puffer and was thinking about ditching my Sunfish setup...but actually is working fine. The previous owner cut the corners for some unknown reason, but they still function and the gaskets are still good and don't leak.. Gaskets aren't too pricey...compared to a new bailer.