FYI, I went for another measurement today, and after 3 days of living on the straight & narrow, I measured 155/98, which to me looks significantly better than Friday's #'s. The highest single measurement on Fri was 179/115, taken on a day when I had not had any breakfast (today's measurement was taken ~4 hours after breakfast).
I've started a spreadsheet to track those 2 numbers and my HR, and will check it every 2-3 days at the same time, under similar circumstances.