[BirdOPrey5]

Here is the complete code to go to 80x80... you can customize the font sizes as you want.

#bop5headcalmain {
  height:80px !important;
  width:80px !important;
  background-size: 100%;
}
#bop5headcalmonth {
  top:18px !important;
  width:80px !important;
  font-size: 8pt !important;
}
#bop5headcalweek {
  top:33px !important;
  width:80px !important;
  font-size: 8pt !important;
}
#bop5headcalday {
  top:45px !important;
  width:80px !important;
}