especially since doing the above as suggested by Virtuali cleared some of the gates.
I never said the update would fit the 777 in ALL heavy gates.
In the update, we increased the radius ( in GSX, so you won't see any difference in the AFCAD, but that's the only thing that matters in your case ) of many parking spots that COULD be enlarged, based on an obvious visual inspection of the spot, so there might still be other labeled "heavy", which should not really considered "heavy", because that's just a label, what really matters is the actual space and parking radius.
If you think there are still parking spots that could fit a 777 but they are not allowed in GSX, that's precisely what the "Max Wingspan" parameter in the GSX customization page does: it allows you to override the radius and let you decide which airplanes can fit there, from a GSX point of view. Of course, if the *actual* available space is not enough, GSX will accept the parking, but you should expect issues with vehicles doing strange things trying to reach the airplane doors.
And of course, if you find annoying having to specify the wingspan on every airport, there's a GLOBAL option in the GSX Settings called "Ignore Wingspan when parking". If this is checked, GSX will allow you park everywhere you like but, of course, if you park a 747 in a place that would barely fit a CRJ, expect all sort of issues to be happening, with vehicles clashing into each other or doing strange paths.