Okay sorry if I sound a bit dismissive, but your world is not ending if 1-2 HB land outside of the pot if it means refreshing your GCD combo if you have this many new tools to do more potency compared to ShB and EW. If there is a general damage problem, surely potencies can be adjusted.

30 seconds has been extremely generous to begin with to accomodate for Reaper and Gunbreaker. If we extend it further, I'm starting to question why have combo timers at all - because we will always hit a new breakpoint at some point. At some point your 35s wont be enough because job XYZ will have to postpone their combo for their 40-45s "burst" because for some reason a 45s buff window exists (new potion extension lol).