You were doing OK until you got to the "aggressive tread" part.We have 285/70/17 tires and don't air down. My thoughts are the wider tires are at least as wide as a deflated factory tire. If you plan on doing some beach driving maybe look into a wider tire with a little more of an aggressive tread. Never had any issues. hopefully I just did not jinx myself. We are actually taking the ferry over to Cape Look Out in the morning.
"Agressive tread" is fine in mud because it gets you down to a solid footing.
In sand, aggressive tread just gets you stuck, as there is nothing solid underneath the sand.
There is just more sand.
A 'street tread' road tire is what you want.
A non aggressive tread is the best tire for sand.