Setting the WB on the H1 and A1 together
 

I have a 3 cameras stage shoot coming up with 1 H1 and 2 A1 cameras, what is the best way to set the white balance on all three cameras to be as close as possible.
Is setting all cameras on K with a fixed value will be the best setting ?
Or set the WB on one fix location on the stage with all three cameras?

Thanks in advanced

Simple have someone hold a large white card on stage under the exact lighting to be used,

then focus all 3 cameras at the white card on stage and do a manual white balance.