My geuss would be a rotor type gennie. Ceramics are not nearly as strong as Neos and things like air gap causes losses of magnetic flux also. My thinking is with a flat face like the rotor type gennies you can get the magnets much closer to the coils (smaller airgap) than you could with a motor type gennie with the round armature inside. Also with the rotor type gennie you can use magnets on both sides of the coils which pulls the flux through the coils, can't do that on a motor type. You'll use more magnets but should get alot more power.
Also of course if these are flat magnets (geussing they are) then mounting them inside a motor type gennie would cause a large airgap in the center of the magnet by the time you get enough clearance for the edges of the magnets. That's the big problem with round motor type gennies and flat magnets. I built a few of the motor conversions and used 2" round neos, very strong, and the big problem I have is I have to cut so deep for the edges of the magnets to clear the inside of the motor that I have a large airgap in the center of the magnet. I get power, but I am wasting most of the magnet strength this way. Would be far better for me to use these as a rotor type gennie and I will be doing so soon. I get alot of motors and had these magnets already so I tried them. I did mount them so I could remove them easily. I could try to fill the airgap with steel over the magnet to fill the gap and that would help alot I am sure, but I haven't done that yet since I was planning to take them back out anyway.
On the other hand if your magnets are curved and you can make a circle of them, then maybe a motor type would work better, if they can be set to have a small airgap on a round armature. I will be getting ceramics from electric motors used in cars for heaters, radiator fans etc.. and these are ok strenght but not strong as neos would be. But they are nearly free and about half round. 2 of these fill the case of the motor they came out of. These are normally mounted to the case so have the same round shape and nearly as big as the motor case. In this case these magnets will not lay flat so they are not any good for a rotor type gennie anyway.
What I plan to do now myself is take apart my motor conversions and remove the 2" round neos and replace them with these half round motor ceramics. Cutting magnets is not easy I think, and I have to cut the ceramics in half before I can mount them for 4 or 6 poles on the shafts. I have not tried cutting magnets yet myself. I've heard you can score them with a hacksaw then snap them in half, I haven't tried that yet. I also heard using power tools can be bad, heat causes magnets to go dead, and possibly a fire hazzard too. Wet tile cutting saw is supposed to be good, have not yet tried that either.
