I hunt the open country a ton and I've had the best luck with a heavier, thinner diameter arrow.

I shoot the Deep Six 4 mm FMJ's in 280 spine and that is the best I've found for the conditions I hunt in and I hunt pretty much exclusively spot and stalk.

Just my opinion after trying several different arrows and diameters.

I'm more worried about holding my bow steady in the wind then arrow drift, that's the tougher part I've found.