RE:Simms breathable waders
On second thought as you are a north shore guy boot foots might be the ticket. The sand is hard and the walks are not like the outer cape, flats or Monomoy. There are a number of rocky areas like Ipswich northside and the refuge. My perspectives were largely from the soft and vast sand deposits I walk on the cape.
As far as size, I always just try them on before I buy. Once again, I like to be able to put on my river boots and fish the freestone with my goretex too.