What is your auw? Have you tried to keep the weight down to aid thermalling? My experience has been that it tends to sink, I mean it is not really a thermal model in my opinion. I tried to keep it light but prefer a heavier set up for higher wind application, for more dynamic flight. So i have a 140g motor requiring my batt to be pushed back to the servo mount to balance, batt tray removed, 2200 4s. 3639 750 kv turning 13x9. Low kv, low amp draw higher voltage more torque to turn larger prop, more thrust. Auw i dare say is heavier that your 3530 set up on 3s? I think you will enjoy the climb rate more so on mine. In a good breeze it will sit there and not drop its nose, a little flap for camber, so long as it is balanced well, light spinner required.
Its a fun plane but not really a great performer, at any specific task, don't get me wrong, i like it, have found it does best with a set up with a bit of authority.