the Regulator can easily handle it , all it does is switch the field circuit ground .
I also agree that the alt just puts out the minimum to keep the system / battery at 14 v but If you are running a lot of accessories you can exceed 60 amps , for example we were running 2 electric fans , electric water pump , EFI , 2 fuel pumps + the usual accessories & the battery was going dead while running so we had to have a 100+ Amp alt to feed enough power , this will overload the factory ammeter & burn or melt it + can overload the wires only rated for 60 amps so I would definatly run the bypass, if the battery was dead for example the alt will go to full charge ! The real question could be asked - is if you do not need more than 60 amps why have 120 amp alt ??