Hello Paul B
I've now been 'tasked' to electrify a third bike and all I can offer is that "it all depends on what you want to end up with." Right now I'm in a quandary over this third project because the bike in question is one with (in my opinion) more gears than are ever needed.
So, I'd be interested to know what others think is reasonable gearing for an electrified bike. (This third project is to be a rear wheel drive and, whilst I'm at it, I think it would be worth changing the gear cassette to a smaller one).
I recently electrified a Brompton for my sister (the result described as "fantastic") and although she has an available 3 speeds in a the basic Sturmey Archer hub, she tells me she's never changed from the middle gear since the switch to electric power (and that's even when riding in the hillier parts of the Peak District).