Are you talking about switching the entire MFD/FKS assembly between skis, or taking the FKS off the MFDs then putting them straight on the megawatts?
If this is the case, you should be aware that the MFDs cannot have bindings installed repeatedly. The aluminum threads on the plates are not the same as the threads of quiver killers. Once you take the binding off of the plate, those holes are ruined due to the binding screws biting into the aluminum plate. Since there is only one set of toe holes, MFDs are essentially one time use regarding binding installs.
Disregard if you are planning on switching the entire assembly.
I really like my MFDs because I can use my FKS 180's and they're on my daily driver. I don't mind the extra weight since they're mounted on Renegades and I'm fat and slow anyway.
If you're not married to having FKS' on all your skis, I'd do what others have recommended and put the 140's on the megawatts then something baron/guardian-esque on the Opus'.
She needs less talking. More dumping them out - SeanTom