27" should be stiff enough. When I find I run out of adjustment and get the same tear no matter how far out I set or how far in I set, I find clearance issues. How are you nocking your arrow? Cock fletch down or to the left? I have a PSE with clearance issues and with blazers I have to set them cock fletch outto the left. Check and make sure they can clear the cables. Switchback should have plenty of clearance unlike my PSE.