Bigger broadheads =more blade surface area. More blade surface area = more susceptible to planing. More susceptible to planing = more critical on bow tune.

Move rest left, move nockset up.

If you really want to reduce the effect of planing, you're talking about doing exactly the wrong things. The lighter your arrows get, the easier they are for the broadhead to steer off course. The heavier they are, the more resistant they are to being drawn off their flight path. Helical fletching is best for stabilizing an arrow andalso keeping it flying straight.

So, go to heavier arrows and stick with helical fletch.