My 20# Dynamax knocks me over when I catch it. I just don’t think I’m ready to use it for any high-volume workouts yet. I wanted to buy a 14# ball, but all I could find at my local sporting goods store in a 14-inch wallball variety was 12# and 16#. The latter just seemed too close to RX, and I was worried it wouldn’t really give me any noticeable difference, which is the whole point of scaling. So, I bought the 12# ball.
It’s amazing what using a “proper” weight feels like. I still worked my butt off, but it felt like a challenge as opposed to just a downright @$$whip. I ended up knocking out 150 reps in 14:10. I did the first 25 unbroken, then did most of the remainder in spurts of 10. I think if I was willing to fight through the pain a bit more, 12 min is definitely a possibility.