Service manual says stator outputs 14.0VAC, 29.6 A @ 5k rpm.
The rectifier outputs 14.3-14.7 VDC with a capacity of 50A, but that's it's capacity rating, not actual output.
I would guess then based on the stator, you have a total of 38amps at 12 VDC to play around with minus the OEM draw whatever that is.