Wow.. Lots of misunderstanding here.. CG has almost zero effect upon an airplanes stall tendencies. Airplanes stall because of 2 things.. Critical angle of attack or insufficient airspeed (generally leading to critical angle of attack). Now if your CG is too far back, your pitch rate can become uncontrollable (due to static instability). Too far forward, and you begin to lack elevator/tail power to effect pitch changes, the most common situation being running out of elevator to land properly.. which often causes a bounce. Granted this is somewhat an oversimplification of things, but CG really only affects stability.
Tip stall is simply one wing stalling before the other. If it's always the same wing, the wing is probably not straight, or the tip has a higher angle of attack than the root (wash-in), or you're skidding around with yaw input. Crow helps fix this because it reduces the angle of attack at the wingtip vs the root, causing the root to stall first, which has less rolling force because of the moment arm relative to the wingtip.
Last edited by Doug Cronkhite; 11-09-2017 at 12:18 AM.