Alternator Sizing - Amp requirements

Well, after some research, it seems I should be looking into something in the 120 amp range. Depending on the power curve, this should produce plenty of power at idle for what I'll be running.

I've been looking into a reworked 90 amp Land Cruiser model wired for 120 amps, or a John Deere 120 amp Denso alternator. My only concern with a 120 amp rebuilt Land cruiser alternator is that since they were designed for 90 amps, maybe the extra windings etc. may cause overheating issues? Is this a real concern??

Alternatively, the JD model is a stout piece - just pretty large.

As far as wiring, I'll likely be sending power from the alternator to a central distribution block in the cab for cab-located accessories, w/ a separate feed for the headlight relays and anything else under the hood.