It's a suck it an see situation. I face a long, steep climp (3 km and on my geared bike, ride it in 30x32) and know what you're facing. Whatever gear you're using, you've got to ride it both up the hill and down so yes, you need to learn to spin, learn to control your leg speed using brakes and back pressure, and learn to climb efficiency. I've just gone to the S3X ... and then got a really bad flu so I haven't settled in to using it yet.

There are two ways of using your S3X. The first is to use top gear as your around town gear which gives you two lower gears for getting up hills. This isn't a bad option because the downhills are only restricted by your ability to spin.
The second way is to use 2nd gear as your around town gear. I've gone this way because my downhill run is in heavy traffic with a dodgy shoulder so I really need to run at traffic speed so 1st gear is my high speed gear (I top 60km/hr every day). Unfortunately, the drop from 2nd to 3rd isn't that great so my lowest gear isn't a climbing gear, it's merely less horrid trying to get up that sodding hill.

You will get a lot stronger as you ride more fg - if you have gears, you tend to use them. If you're young and fit, you may wind up climbing your hills. At my age, it's not likely to happen so I spend a lot of time using the 24inch gear (two feet).