Thanks everyone for your replies...

Next time I'll fly with the rpm I want, and use Carb Heat below the
green arc as the POH recommends.

BTW: the Bay Tour definitely causes 'Ohh's and 'Ahh's. Even the first
two times I went (no pax) it was tough to stay focused on
traffic/airspace and not just enjoy the view. PS: Now (with pax) I
won't touch a camera at all, and just scan for traffic - as I've seen
quite a bit of traffic going North/South between the GGB and KHAF -
not to mention the low flying tours around the GGB and San Francisco.

Cheers,
Noah