I did an exclusive review for Gearslutz... and so here is the direct link, which includes two videos (one that runs through some high-gain, metal and insane amps... the other goes through a short tutorial on how it works):
https://www.gearslutz.com/board/reviews/1210657-bias-amp-2-positive-grid.html#post13247836
https://www.gearslutz.com/board/reviews/1210657-bias-amp-2-positive-grid.html#post13247836