Display Cabinets

I use the IKEA Billy range of bookcases, using their glass doors and shelves, for miniatures, and the wood ones for games, books and magazines.
In order to get more shelves into the miniature cabinets I drilled extra holes into the cabinets sides before I assembled them. I have created versions with either ten or twelve glass shelves per unit (and two wooden ones).
The ten shelf layout has six inches between all the shelves, the twelve has six inches at the top and bottom of both the upper and lower section, but five inches for all the other shelves.
In both cases the same extra shelf holes are required, but in the twelve shelf layout, the doors are also inverted, which requires new hinge screw holes.