To turn a gen 3 City into a double chainring + cassette tranmission, what Hollowtech crankset and rear hub should I get?

I already have a Litepro clamp, a 2s braze-on, down-pulling front derailleur + 8s rear derailleur, dual chainring, and shifters available.

According to Sheldon, a 50/34 and a 11-32T provides a 1,5 - 6,2m development, good enough for touring.