Oof, my gearing wouldn't get up that. My commute is mainly flat so I prefer the larger gear to tap out a good tempo, and I can take on mellow hills, maybe up to about 5-8%. I ground to halt the other day trying an unfamiliar road, had the ignominy of pushing up, of course people assume you're knackered rather than being unable to turn the poxy cranks!
The Guerciotti takes care of the hills, hate spinning like a madman down the other side when you're riding fixed, although props to people that do, I'd need a shorter gear, probably about 60inches, but then then I dislike the spinnyness on the flats and the lack of a good top speed. 51x19 gives me decent speed on the flats, except I still get blasted by roadies mashing the big ring and a little sprocket