Personally, I don't find smaller diameter tires any harder to work with. Fat tires, on the other hand, can be a little trickier than narrower tires just due to the size. However, if you're accustomed to fixing flats on other bikes you shouldn't need any special tips or techniques.
I agree with Ann in that a conversion should be no problem. As to kits, there are lots. There are a number of kits reviewed here: https://electricbikereview.com/category/kits/
As you'll see, many of the kits are quite expensive but there are some more affordable choices too. You'll also find...
Exactly. When I said I question the location of the battery, I meant I question whether it makes sense. Thanks for the exploded view of the hub though. Very cool from a technology perspective, but not sure from a cycling perspective.
Yeah, I read somewhere that they changed the name. I thought Elektron was the new name, but I probably have it backwards. Regardless, very cool that you got to ride one! I'm jealous. :-)
Check out this striking new Icon e bike from Italy's 43 Milano: http://newatlas.com/icon-ebike-43-milano/46165/
I love the headlight & taillight incorporated into the ends of the top tube. :-)
Of those mentioned, personally I like the Electra Townie. That's partly because I love the classic cruiser style, partly for the Bosch drive, and partly for the internally-geared hub. BTW, kudos for still riding at 76 years young!