Not including practice rounds, I think the only time I screwed up was at nats when I had to do a stack by the bar and a stack in the middle and I didn't quite make it back in time. I had never practiced it though, so I think it's ok
And to add a little bit of humor...I am only 4 bins high...so at Cleveland the announcer always had to peek around the stack to make sure there was someone there...small but mighty!!
