Originally Posted by
tonei
I've gone and spent time in Seattle with a layover half that long. 10 hours is plenty. And Ken's is a great place to leave your bag.
+1...heck, I make day trips to Seattle for under 12 hours relatively often, arriving at 8:30am and heading home on the 745pm departure.
Kens is operational and a great place to store the bag.
for PreCheck, yes FI will not offer it. if you feel you must have it, buy a refundable domestic ticket, check in and use the BP to go through, then cancel it for a refund.