Yavid; on my MM3-2 the centerline of the top two roller bores to the lower centerline of the single adjustable eccentric adjustment without the eccentric installed I come up with the same measurement distance apart.
Looking at the plate from the roller end view, (inside the mill), top left driven roller, top right drive roller. If the top right drive roller is turning CCW it is pulling the grain thru the other top driven roller that must turn CW by the grain for the 0.060" crush. With the eccentric gap set tighter to the drive roller this bottom roller will turn CW driven directly by the drive roller from the already precrushed 0.060" grain, the wider gap between the bottom adjustable roller and the top left driven roller are both rotating in the direction to both push the grain back up not down thru the wider gap. Like you running up a down escalator both rollers acting on the grain. In this position the tighter gap adjustable roller is driven by the grain between it and the drive roller. To rotate the eccentric to the left the bottom roller will change from a CW to CCW rotation plus must be driven by the left driven roller. This will compound the slippage amount being rotated by a already driven roller above by the grain alone vs directly off the right drive roller. If you insisted on setting your gap between the two driven rollers the bottom adjustable roller will wants to push the grain up while the right drive roller with a wider gap wants to push grain downward vs going thru the set tighter second gap. Clearly this is a bad idea, for one two opposite directions to keep the gain up in the mill vs two rollers in the same direction keeping the gain up in the mill plus your then using the top driven roller to drive the second adjustable roller that's driven doubling the possiblity of grain slipping between two rollers vs one. This make any sense now? See the two bad reasons? One should remember to set the gap against the drive roller not the top driven roller on the MM design of mill. With the extra cash at hand I knew I wouldn't be happy with a 2 roller so went for the 3 roller of 2". Case hardening was just added icing on the cake plus free only a 3 mile drive. I added extra labor polishing the journals before to remove the sharp machining journal surfaces then after the case hardening process plus added vinyl tubing protecting these journals then used fine bead blasting at a low pressure to clean off the dark knurling color from the case hardening process.
Hope this helps.
BTW; I wouldn't get all hung up on roller speed differences for the crush as the MM knurling is rather agressive they go to a sharp point not just hash marks on the rollers like a shallow knurling job.
My take on this with different roller speeds you'll be making a shredding machine with more flour and grain damage vs cracking and crushing the grain. JMO.