Great job on this bike, man. Love it.
The 42 seems a bit limiting to me. 42/28 is quite tought (at least for me) for regular road riding (in Belgium), let alone with luggage. I'm quite sure it's not possible to mount a smaller ring on these cranks though. If you want vintage cranks and small bcd, campagnolo victory/triomphe is an option. Then you could install a 36 or even 34 Miche chainring, I think.
But it looks great now, so if you're ok with this gearing, just keep it as it is. The polished cranks looks gorgeous, especially with those anodised rings.