Sounds nice. Here in the summertime it is so humid that some days both heat-pumps are running continuously, but since they tie in outside I don't believe the 100A sub-panel is affected. Same story in mid-winter though much less often, if the outside temperature drops much below freezing, both heat pumps will have the auxiliary heating elements kick in. But most of the year it is mild and neither heat pump is actually running much. And I wouldn't be running more than one of the dryer, stove, or amplifier at a time.