I've been playing around on mapmyride.com, and the elevation measurements are pretty wild on that--which is to say, somewhat inaccurate (ascents where I don't see them on the bike, and vice versa). But in lieu of anything else, I dragged the csv data into Works, and got some crazy numbers for my one big hill: spikes all over the place. One datapoint indicated 31%!

I picked a couple of points, and in the span of about a kilometer (or 0.6 miles), I found about 6%--but plenty datapoints indicating numbers like 12% or worse. So, for that hill I'll call it a 10% grade. I use 40/30 to climb that. I kinda just shift down early, as it's at the end of my ride, and I just spin for like a mile (or what feels like that). OTOH, this is my fast hill: 40mph (67km/hr) in 52/13!

As I pick up some strength, and if the wind isn't in my face, I'm finding that I might climb lesser hills (5 or 6% I'd guess) in something like 40/25 or even 40/21, if I have some speed going into it. I don't have a way to measure cadence on the bike, but I'll guess I'm at 70rpm (I verified once a couple speeds versus gears at 90rpm, so it's a reasonable guess) when cranking up the hills in the higher gears.