Soloist sizing help - stuck between 54 and 56

I have a 90 mm stem and 20 mm of spacers. My “prescribed” numbers are:

     Saddle Height over BB   77 cm  Crank Arm Length 172.5 mm  Tip of Saddle to end of Aero Bars 70 cm  Nose of saddle to BB -2 cm  Aerobar Angle +4.5 degrees  Saddle Horizontal Tilt +1 degrees  Aero Bar Pad Width (Center) 21 cm  Aerobar Size/Extension 33/S* cm  Top of Saddle to Top of Armpad -5 cm  Knee to Pedal Spindle +1.75 cm 

As a side note, here was my position before getting fit:

    Saddle Height over BB   76.5 cm  Crank Arm Length 170 mm  Tip of Saddle to end of Aero Bars 77.7 cm  Nose of saddle to BB -6 cm  Aerobar Angle -4.5 degrees  Saddle Horizontal Tilt +2.6 degrees  Aero Bar Pad Width (Center) 26 cm  Aerobar Size/Extension 35.5 cm  Top of Saddle to Top of Armpad -4 cm 
  • Medium aerobars would also work from an arm length perspective, but would likely cause knee to armpad interference