Dowbell, I also live in the Greater Renton area. Actually my Weather Station location to NOAA says I am 3.2 ms due East of town. I grew up out here when it was only forest n small farms among the trees.
In our region it is advised to use two deep boxes. One is your main brood box n upper deep will usually be your winter honey supply. The new Flow-hive would eventually sit atop that second deep super.
I am returning to beekeeping after a 55 year break. I raised bees as a school agriculture project for 7 or 8 years. I will be receiving my 3 Nuc's of bees about mid April 2016. I am building n assembling my hives this winter in my small woodshop.
If you read this n are interested .. We could meet someplace for coffee. I can be reached here or my E-mail email@example.com but use a header "BeeKeeping" so it does go to my auto trash can. Hope to hear from you.
Coalfieldbeelover - Gerald