... He seems happy enough with the 80" gear he has at the moment, but I think he will do better on the hills and also at leg braking with a 68" gear.
80"
On Vince the snow and ice bike which I'm mostly using at the moment, I've got a 58" (single speed not fixed). Admittedly that was selected for easy and cheap availability of a suitable freewheel, and making sure that I can still get up silly snow and ice covered hills, but an 80" gear would be stupid for me on London's flat roads. Around your neck of the woods, I would have thought it was horrendous!
I just had some spare bits for my older Dinottes lights delivered. A rear mount, and enough rubber mounting bands to keep me going into the next century!
It also got here using USPS International First Class in about half the time that USPS International Express Delivery took, because it was below the threshold for VAT payment, and was a very small packet, so Parcel Force had no chance to bugger it about, like they did my last parcel from Dinotte.