So we rented a little cabin for the week of labor day right on sagamore beach

I have never actually been over there. Is it worth wetting a line on the beach or should I just walk over to the canal?

That time of year I would say yes it's worth it.
keep an eye out for birds at first light or chunk at n ight

Cool.. thanks for the tip... :)

That whole stretch of beach can produce. Birds can help you key in on specific spots but check it out at low tide for channels, bowls, sandbars and further North rocky areas.