Remember that the Eko ones are made for a solid headstock rather than a slotted one so the posts might not be long enough.

One solution would be to start off with a "normally" spaced set and cut them into 6/12 individual tuners. Grind/file off a sufficient amount between each section of base-plate and secure them with a screw between each + one at each end. It's been done before with pre-1920's Gibson mandolins (StewMac has only started to produce tuners with the "old" spacing in the last decade and it avoids having to re-drill the headstock).