Oh, except one thing:
The time_t returned by RTC.get() is epoch time ( seconds since Jan 1. 1970 ), so I'm only multiplying by 60 as opposed to 60000.. The final function looks like this:
void adjustTimeEnc(int deltaTime){
unsigned long newTime = RTC.get() + deltaTime*60L;
RTC.set(newTime);
ShowTimeOnDisplay();
}
The last call ShowTimeOnDisplay() makes sure the display updates every time the time is changed.
Any ways! Thanks again!