Hi,
I took a long time, but I finally found a place to publish the 3D gates:
Les portes de camp en trois dimensions sur le monnayage de Constantin : une recherche laborieuse de perspective (Rome, 320 apr. J.-C.) (2018: Lars Ramskold, Bulletin de la Société Française de Numismatique 73 (7), pp. 317-323).
So far, those three are the only known examples. In time, more will probably come to light.
/Lars