Is you alignment corrected? Best practice is to get 4 new tires, of have the 2 new ones shaved. you could probably do what you are saying, but with the alignment corrected, it should not wear the way you want them to, to make them even.
make sure you get a good alignment if you havent done it yet.
4-Time NNJR ESP Season Champion -15 ESP
3rd Place in 09' Pax Championship/Driver of the Year
2012 Northeast Divisional Champion in ESP