That looks on par with Ventoux which is an average of 7.5% for 13 miles.

Only problem you may find is gearing. I used 28/28 all the way up and this may have been my problem. When things got tough I got into the lowest gear and stayed there.

So if you are looking for speed- fit the standard crank with a 42 small sprocket and the 11/21 cassette. Then you won't be tempted to crawl up the mountain in a low gear to make it easy.

Good Luck and enjoy the ride.