Marking that one off my bucket list.
I had read once that when you hit 70 in a set, that 200 was achievable. By my experience today, that seems to be correct.
Also, in learning the basics of Tai Chi I have been working on my breathing. I have been taking a deep breath on the down motion of the squat and breath out as I moved up. This changed the pace, and gave me more strength.
My day went first a set of 70 after doing Tai Chi. Then a set of about a 100 at the end of lunch, but then the bell rang so I had to go to class. And then I set to match a 100. When I hit 100, I just kept going thinking I would get extremely fatigued. Around 170, I was confident I would reach my goal. I pushed through to a set of 210, just in case I had miscounted. Therefore, I am absolutely certain that I have done 200 squats in a set.