I would think it would wind the Nr up very quickly if you introduced that much airflow suddenly into the disc from below with zero collective pitch!
There is nothing in the rules that says you cannot finesse entry into autorotation by lowering the correct amount to stop the Nr going crazy.
Tourist - you don't carry out the EOL from a zero speed condition, you adjust to normal auto speed before that and only use the zero speed to help you reach your aiming point. A constant attitude EOL is still done from 30-40 kts IAS so lots of forward speed.
Not when I went through Wallop. I still remember with some horror the zero speed EOL. It was near enough vertical in the Gazelle.