when you use the Mikrotik large outdoor case i think you need to use some extra "nuts and bolts" to find a space under the RB to use the extra 2 Minipci slot on it , its littlebet difficult but you should try it.
Well, some of us don't necessarily use all mini-pci slots, but prefer sockets incase one more more dies. I wanted the Micro-SD slot and the USB slots myself.