i understand the amperage needed in a totally [or almost totally] discharged battery will be very high, [your graphs are good by the way] and as you approach 40 amps charging, you are closing in on dangerous territory as far as charging goes, but i think my main question is, can you safely use a 60amp gauge on a say, 100amp alternator system ?
this, of course, is using the bypass diagram you posted above, and your wiring system is in good working order.

for the last many, many years, all my wiring [original harness and from scratch] has been centered on using a volt gauge only, [in creating a new harness] and disconnecting the original amp gauge, or converting it to a volt gauge in an original or reproduction harness. now, high amperage alternators are a common addition, and for one of my own projects, i would like to run an amp gauge as well as a volt gauge, but was somewhat concerned about the available amp gauges only coming in at 60 amps. [if a guy has a draw or input of that amount, you have problems ! ]

comments ?