Perhaps if you tried the same mod with big ring Neo's instead of ferrite magnets, you could double the flux (or more).  That would yield a better V/RPM ratio.  Still fast, but on a small mill, might be closer to the ballpark.

i was often going to try the same thing myself.  only use neo mags and replace the shaft with a stainless one.  the stock shaft in my belief, robs too much flux from the mags.  a stainless shaft, will allow all the flux to be concentrated on the claw rotor.

you went this far, maybe use the same unit with a new shaft and see what happens.

This is an experiment I've been thinking about for a while, too.

I think that a new shaft arrangement is needed

If still after a new shaft is installed, there is not enough power, you might connect two alts together on the same shaft.

Looking for your next results.

  I noticed hydrogen appliance was modifying the alternators by using a very large and extreemly strong neo ring magnet and a friend had purchased several of them for testing purposes.  Unfortunately their output was far less than they advertized.  

  I started making new rotors from aluminum and putting a steel backing to secure the magnets retaining the original shaft.  The magnets were simply the 1 x .5 x .125 mounted around the circumference of the new rotor.  This made a significant difference in output but still required 400-500 rpm for `12volt cut in and definately created a cogging issue.  I concluded if you could get some custom wedge magnets made up the cogging would be eliminated and the output could be increased considerably again by using a 1/4" thick N35 magnet.

  Also, you can grind the pins from the laminants and put several alternator cores together, use a longer shaft and still use the end housings for the bearings.  It looks a little odd but you can put a lot of wire in a 4 core alternator.  You can also use the smaller magnets in the longer core and stager the magnets to reduce the cogging.  You can use spacers on the original winding/core to separate the cores to use as is...

  Lots of cool options with them, thier a pretty simple and versitile little alternator.  I used to have a huge box of the old Delco's ( 35 amp ) but I went through them pretty fast playing around and ended up selling alot of the modified versions.  I haven't been to the junk yard lately so I don't know whtt they cost anymore.  

  You can also make a small PM alternator to feed the field coil of a stock alternator which works fairly well too, although they don't do real well in low winds.  As the wind increases so does the load.  

I had lots of fun with the old 10si's still have 4 or 5 laying around for future fun when I get time.  

Keep up the great work!