For the record, a real good pond builder would have recognized what you're doing and would have made strong suggestions to either support or challenge your plans. I think I would take that approach of "looking for his help and tapping his years of experience" to help avoid a poor logistical decision for a nice beach. My NRCS guy once told me nothing trumps ground truth when it comes to preparing excavation. Let your dirt guy help you make the decision. If, after you consider all we have discussed here, he says that a beach and swimming area would work out just fine within the cove, perhaps you will have learned something about HIS expertise and wisdom.
