+1 wkg: big ring. This will help develop excellent power & the bigger gear will help maintain smoothness.

We have a similar hill on a training ride out here in SoCal: 0.2 miles long, 6-7% avg gradient. The climb begins on a right-hand turn. We approach & roll through the turn at about 20-22mph.

When I first started doing the training ride, I would drop down to my 39t small ring and try to spin up the hill. (I'm a bigger rider & this is conventional wisdom for us: sit & spin.) I summarily would get dropped.

I then noticed that all the other riders were in their big rings (52-53's). Next time up, I left it in mine, too and flew to the top, easily keeping up with the group. Doing it ever since.