The overall fit (stock dimensions) is probably more important than achieving the same sight picture via adjustable ribs on both barrels of a combo set. With corrective lenses set for distance vision, the rib and bead appearance is not a big factor, particularly if you shoot off of the front end of the rib.
I bought into the marketing hype of adjustable rib combos and tried a MX2005 (unsingle) for about two years with poor results, traded it for a MX2000/10 (top single combos) and have used it for about the same amount of time. Neither of these adjustable-rib combos provided any advantage over my fixed-rib MX8 combo - I have reverted to the MX8 and get a few more targets in each discipline than with either of the other guns.
Note that the difference noted above is likely to be more related to stock fit than to rib adjustability. The MX8 is equipped with a fully adjustable (Precision Fit) stock which is set for a high POI (big gap between the front and middle beads). The others had or have adjustable combs and butt-pad assemblies and were set by patterning and shooting refinements to the same POI as the MX8. As part of the adjustment process, the ribs were set to get a smaller gap between beads. The adjustable factory stocks were close to being "right" but just far enough off in terms of cheek pressure and head position to cause problems over the course of long tournaments - the "improved" sight picture did not help. I am making one last attempt to salvage the MX2000/10 by installing a custom stock this fall.
But, you should try the adjustable rib combos to see if they work well for you - shoot enough targets with whatever you are considering to get past the new-gun syndrome before deciding.
Good luck with your search,
Pat