I agree with the "DON'T DO IT"...
I hit similar up/down draughts in the sierra nevadas in Spain on a ferry flight back to base last year, the only thing that happened to my 205 was loss of RPM! All the horns and lights went on and frightened the c... out of me but instinct luckily took over and I dropped a bit of collective and all was well.
"Helis and -G don't mix" Well not exactly, you can play a little bit with rigid rotor systems but very gently, but not with teetering systems....NO WAY!