I normally don't like shooting people that much, because I like to experiment with settings, lenses etc. to get a result that I like, so it helps when the subject doesn't move (Mountains and buildings are especially good at that).
Now I have been asked to shoot my moms wedding (not with brides dress or anything fancy), and I can use what equipment they have there.
I have available a Canon 5DMKIII and a 6D and in order to not have to quickly switch lenses on one body (after which I am sure the subject of the photo I am going to take is gone), I was planning to take both with different lenses.
The available lenses are (well, there are some more, but I don't think a macro or tilt shift will be of much use there):
EF 24-70mm f/2.8L II USM
EF 70-200mm f/2.8L IS II USM
EF 50mm f/1.2L USM
I will want to cover several situations and locations, first the ceremony is in a not so well lit room where no flash is allowed. I am planning to use the 50 prime for the ceremony part, some portrait and close ups of maybe fingers with ring or signing the papers or whatever will happen (I am trying the "invisible photographer" approach, people should just ignore me, no "can you hold this a moment" stuff), mainly due to the bad lighting conditions.
Then for getting outside a bit I thought about the 24-70 being a bit more versatile (I am hoping for at least a bit light, although forecast says rain) and then for shooting small kids I like the 70-200 most, because usually when you approach them, it destroys the moment you want to capture (at least thats the way it works with my kids).
So I am leaning towards using the 5d+50 for indoors, and then the two bodies with the two zooms for outdoors and the bigger, more lit rooms.
But what are good criteria to match which of the bodies to use with which lens? 5d+24-70/6d+70-200 or 5d+70-200/6d+24-70? Or am I overthinking this and there will be no real difference?