If this mod proves doable, it will be the new budget mod.
$12 includes shipping.
Not a 16T, but a 15T ... as pictured.
Large enough in diameter that alignment with freewheel must be fairly precise.
The good news ...
Fits snugly on eZip GR shaft.
Of course, you will also have to lengthen the chain.
click on picture
This mod by itself will increase (some) assist, from 18 to 30+mph - actual speed from 16mph to mid twenties?
As a solitary mod, might require no re-alignment.
Now that I consider it, might be able to do the mod without any disassembly of the rear.
Loosen motor bracket,
Mod "key" (see 12T upgrade),
Replace chain with longer, and repair link,
retighten motor bracket, done.