I would go with the thicker polymer unless I was running only was and well known grass flats. However, with tropical storms and Hurricanes, shoot propane tanks, hot water heaters, logs and everything else gets moved around out here and even worst in LA.
Flew over the marsh north of where Holly Beach, LA was, it is now all out in the marsh, a line of debris that looks miles long. Sad to see the Cajun riviera all gone. Drank lots of cold ones there and talked to lots of gals.
But back to the thread, so even in the marsh I would go with the thicker polymer. Know a guy that hit a ancient marsh buggy abandoned in the marsh and I barely missed a tractor that is stuck in the marsh. Apparently got stuck by in the 1970 and just enough remains that you can recognize it for what it is.
That little bit extra thickness sure seems to provide alot of extra protection.