There are some conditions for MPPT charge controllers where you can mix different panels by matching volts or amps (not watts). This is probably not one of them though.
If you wanted to get the voltage above that 32V threshold to use the higher 20A limit, but stay below 60 Voc, then you'd look for a panel to put in series with your current one to stay around 54 Voc, which would need to be a 17 Voc panel but with matching amps Isc and Imp. Basically I don't think that really exists.
You can also put different panels in parallel that have same Voc and Vmp, but different amps. Doing that adds the amps together. But since you're already hitting the 10A limit, and if not that would hit the 20A limit already, there's no power benefit.
The only other thing you can do to get around the 60V limit, is to use an external 48V MPPT charge controller to feed the DC input. The output of a controller for 48V batteries is right around 54-58V, which is ideal. For example, Victron has a high-quality 150 Voc controller, so you could put 2 or 3 of your current panels in series, and it would output around 58V into the 767. There are lots of cheap Chinese 150 Voc controllers, however, most of them also need a 48V buffer battery wired in parallel with the 767 input, to wake up the controller and set the reference voltage - the Victron can wake up just from the solar input, so does not need the buffer battery, but it is expensive.