Thanks for clarifying that. You have the return path. I think your air gap is probably excessive for those magnets but at least it gives us something to start from.
Can you please let me know if that is the total wire length or the length of each individual wire so that I can get an idea of the resistance.
You will not manage an effective 2 layer winding with thick coils, you will loose more in the end windings than you gain. If the figures look reasonable with the wide gap it may be simper to keep it. To do a 2 layer winding to advantage you will need the thin coils and narrow air gap, it depends on you gaining enough flux from the short gap to let you work with much less turns to gain. Yes the 36 coil version uses coils with half the turns.
You seem to be going about the furling the right way. I would strongly advise you not to short the winding in high winds. It is a good idea with very oversize and powerful alternators but with a light alternator it will almost certainly break loose and it will get very much hotter dissipating the whole power into the winding than sharing it with the battery.
Your figures for cut in are correct based on 1v per coil.
Flux