Seattle hills require a kit for a French beginner. You can do high rev 50cc but no 50 is very good on hills.
I live in the most brutal hill country and 50s will climb them yes, but never as robust as a 70. They just don’t have the torque unless you’re right in the band.
Run any 70cc kit, and er3 with idle function and a big pipe like a circuit style or Doppler.. You’ll have to pull start but the treats cdi flywheel has threaded holes you can add alllen bolts to for a rope start. (edited)