That magic gear calculator is awesome!

I found a combo that works but it meant using the crank off another bike, which is OK because the chainline with this crank is spot on.

I measured the chainstay length at 40.7cm. The calculator came up with 39x18 for 57 gear inches (too low) on a 40.736 chainstay. It works but I think there's too much slack in the chain (new chain BTW).

Next I'll try 53x21 for 66 gear inches (just right) on a 40.761cm stay length. I have a 53t chainring, just have to get a 21t freewheel... might just put that Eno hub on hold for now, I think.