It is true that at faster speeds 2 blade heads can plane or cause a lift.But with the newer BH out today you realy don't have that much of a problem.

You can add bigger vanes or more helical to stabilise the arrow in flight.I shoot magnus stinger 2-blade heads out my Mathewes Switchback and have had no problem with planning even at the 280 fps + mark,I have seen guys shoot these BH at speed of 300 fps and not have any problem.I shot these heads side by sibe with feildpoints and had minimal POI on the target out to 60 yds.
I shoot The Nudge arrows @ 27.5 inch with Quickspin vanes no R-or-L helical on them.
If you are shooting 225 to 280 fps I see no reason to change your set-up.
BBJ