2 bodies one flash

I'll be shooting a wedding in a few weeks. I'm going to have two off camera speedlights for one camera and and use the other camera with a speedlight in the hot shoe.

one camera is a 6D one is a 5d2.

which camera gets the speedlight and which gets to trigger the off camera lights.

i want one body to have the speedlight attached for walking around off the floor.

im thinking the 6d to not have the speedlight because it will focus better with out the assist but i thought maybe the better ISO ability would be better to save some recycle time and help with the ambient if i used that with the speedlight instead.

What are the off camera speedlights and how are you setting them up?

Yong Nuo 568 ( i think, i dont remember their numbering) on camera in a canon 430ii.

I'm setting the off camera up to trigger individually or together, i can control that from my trigger. intend to set them up on opposite corners of the floor one to provide main light and one for rim lighting.

Just going off what you said, I'd probably put the hotshoe speedlight on the 5DII.

In the end, I don't think either would be the wrong choice...but I'd probably err to the side of being more sure I can get focus without the assist beam, rather than make sure my speedlights don't fizzle out.

What kind of power setting do you typically use the off camera flash at? I can't remember a time I've ever had off camera flash at a reception higher than 1/16...normally lower than that.

I have a flash in each hotshoe for focus assist. I also use flashes that can take a battery pack, usually the 8xAA ones from ebay, and I often have a battery pack either in my pocket or clamped to the light stand.