What you need is a variabl camber airfoil (flaps). If flaps are permitted then a relatively thin airfoil with flaps mixed to the elevator will extend the range of coefficients of lift and with the low drag you are looking for. To keep from loosing too much speed in the turns, the flap travel should be limited to about 5 degrees. With careful design of the hinge line and a thin airfoil, the drag won't go up much with so little flap but the increase in lift will be substantial. Go with the MH33 or S6063 and 22% flap width. Use full span flapperons. Don't make the tip chord less than about 75% of the root chord unless you want easy spin entry and snappy snap rolls.