In a restaurant, you would use a scale, it is quite fast actually. Once you get the hang of it. But, I have seen everything from dishers (like ice cream scoops, well, they are ice creams scoops) to plastic cups. You fill with meat product, flip onto bun and serve.
Very efficient and almost as accurate as weighing.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"perhaps...but then again...maybe not..."