Steve wow you have the set up! I think Seattle stays warmer than where you are. A couple years ago I used the same setup only without heat and lights and the tenders did fine! Just to be clear, the semps wouldn't want heat, they are alpine succulents (mountain areas above treeline) But yes they do want dry, so under eaves is where I keep mine, as well as using a hoop system and plastic tarp on some areas. I do make sure there is plenty of airflow, so I secure the tarp about 6 inches from the bottom so there is air on all sides of the bed. (this is for the semps. - in one bed though I am experimenting and have a windowbox of aloe in there - I think if they're dry they'll be great!)
The tender succulents on my deck are definitely vulnerable to freeze, so I'm hoping for at least some warning before an arctic blast if we get one at all this year.
