their h.d. mags , around 1/8" thick and .75x 1" or so
i'm getting 16 poles on doubled up 10 inch rotors.(saw blades)
the coils are two in hand about 28 gauge.
so Ive sacrificed the amps to get a charging voltage at a reasonable rpm.
your using 18 gauge which is modest for a prop job but kind of fat for a 6"dia vertical alt. if you know what i mean.
next i want to open up the alternator dia to some thing like 24" to match the dia . of the vanes.
40 or more poles and the mag thickness can be modest.
by increasing the frequency i can reduce the turn count and fatten up the conductor .
your only going to get what the wind can give you but
is it impossible to get wider PVC pipe so your exterior design can stay about the same.
but the alternator can grow.