I suggest a wing nut and large washer for the wheel bolt. I picked up a 7" x 3/8" carriage bolt today, along with some steel strap, which I'll double or triple in thickness. I intend to go in through the top only, running the bolt through the rubber plug and into the strap, which I will use to bridge the hole. The plug will then be secured to the bolt with a nut, and the spare will be secured to the bolt with the brass wing nut.
2013 "Brilliant Silver" SV with Premium and no QC, a 2009 Vectrix VX-1 W/18 Leaf modules, and 3 EZIP E-bicycles.
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.