Hi Frederic
You don't need the breakeout. Its just a sort of Basis for connecting different Modules.
You can try to extract the pins you need with this schematic (http://ucapps.de/midibox_ng_manual_lcd.html) and the schematic of the Core.
My pcb is made to fit 0.96" oleds. What size are you targeting?
Best regards
Novski