Waco, No, you cant put an ag plane on it's nose by using the beta range. Maybe full reverse and a heavy application of brakes, but not beta. As far as directional control, There again, beta itself is not too bad for control, It's when you come on back into reverse that can really get interesting.
And yes, it is due to the lack of airflow over the tail. And yes, You will be doing a dance on the rudder pedals to keep from going in the ditch.
First turbine I bought was a Ag Cat with a Garrett -1. I thought I was getting good with it and could land on a dime. I told the ground guy to watch me land short. Really came close to busting my ---! Took all the air off the tail and was headed for the grain bins. Not very smart, and I didnt do it again. Whats those famous words? "Watch this". There is a good reason those two words are very dangerous in aviation.