What model MPPT controller are you using?
If the controller has a max input voltage greater than 66 volts, you could try
One string made up of 1 x 12v panel and 1 x 24v panel wired in series.
One string made up of 3 x 12v panels wired in series.
Parallel wire the strings to the MPPT controller.
This should give you a no load voltage of about 60v and a loaded voltage of about 54v at the input of the MPPT