I can't comment on one being used on a Mec 9000 but I can tell you they work great with Mec 600 jr's. I have used a pair of universal charge bars since the late 70's without issue. I pay no mind to the numerical settings and the accompanying literature. I set the bar openings to throw exactly what I want be it lead or powder and confirm the throws many times with a balance beam scale. once I confirm the setting and it is a setting I will need I drill the bar through to accept a 1" finishing nail and mark the hole with an engraver so I know what it is. If I want to return to a certain powder weight I turn the dial until the wee holes line up slide the nail through and lock the set screw. Confirm the first several throws on the scale just to make sure and your good to go. It has worked like a charm for me anyways for a lot of years. Like you say it saves buying and playing around with a piles of bushings which I never found all that accurate to begin with, especially when your dealing with the larger shot sizes when doing hunting loads. Getting consistent throws can be influenced greatly by the vibration in your machine while being operated at various stages. The universal charge bar can be set take operational vibration into account, bushings can not unless you want to start custom drilling them.