fx-85ms
For this Summer all A320 & A321 will be used for ZB flights, as they have reduced seating for the ZB flights.
However A300, A330 will be operating some ZB flights during the summer and l hear the B767 may be also.
The B757 may fill in for the odd ZB flight, but they are back to charter config this summer and one a/c is a back-up a/c for the summer.
The A320 & A321 may also fly the odd charter rotation as well, especially at night.
Hope this is of help.