If you are watering when the soil goes dry at depth, you are watering at the right frequency. Once a week could be perfect at this time of year, but the way to figure that out is to check the soil moisture (not just at the surface, which dries out sooner).
The spots you have identified look like mechanical damage to me. What you need to be on the lookout for are changes to black or brown, or changes where the tissue of the plant feels soft. Leaf damage is absolutely nothing to be concerned about (as the leaves will drop in the near future), and a bit of stem damage just gives your plant character.
I see no connection whatsoever between your primary concern and the watering frequency. Your plant looks like it's really thriving.
Provide the maximum possible amount of sun if this will be an indoor plant. Closer to the window would probably be better. Ideally it should sit right in front of a sunny, unobstructed southerly facing window and "see" the sun for hours a day year round. Light is important during any season but especially important during late fall and winter (and given the climate in Portland, that's when the sun tends to hide for weeks at a time).
