I had not expected that the response to shagbark hickory syrup would be " yeah, I tried that". It turns out After checking my notes I used 2 cups, i presume at the end of boil, but also I racked into secondary with wood chips and a quart of shagbark hickory syrup. It sat for 6 weeks in secondary. It was really fantastic. It was the best big beer I have made. It had a strong alcoholic component which I'm sure was enhanced by the syrup in the secondary but wasn't what I would call "boozy".