Got lucky and the buttons aligned pretty good on this dual setup. If it's close, can adjust bottom or top
as both ends have springs. Not sure what to do with this setup except maybe to show off to someone. Not
really practical, but kind of fun (.......very fun) just to mess around with. Got the condescending look from
my wife again so maybe worthwhile for that alone 
Is that for real? A little bit funny light
yeah, these lights can run on both ends. In real it's ridiculously large and looks like something Thor would carry around. Fun for a few hours, but in the end I took it apart and have two separate lights again.
The MF01/MF02 or M01/MF04 combo is more useful as you get flood/spot combo.
Not that I would ever do this…
MF01/MF02 looks like the best combo. Since there is a spring at both ends if you use two lights, it appears as though the o-rings will not do their job in case of too much moisture as you can't get a good enough seal on at least one of the ends.