Well my mkiv is due here tomorrow, i really cant wait.
I do have another question that i have looked for but cant find.
Ive read a few reviews that mention that due to the larger sensor in the mkiv you need to use faster shutter speeds for moving subjects to avoid blur as the subject passes over the sensor. The theory makes sense but i want to know if there is a guide line, like for hand holding, or is it just trial and error.
Or is is it just something to be aware of and not worry about it until i see issues?
I would stick with your 5D3 settings until you find a need to change. The AF system in the 5D4 is much better, and that might be enough to get more keepers (or at least the same amount) with moving subjects. If you have to shoot faster, it shouldn't be by more than 1/2 stop. And the improved ISO performance in the 5D4 can handle that.