HATE the shuttle. Glassware is usually loaded for all flights, bev or meal, but not always. Also if you have many segments for the galley you can run out of the real glasses.

As for service suffering d/t serving Y, if I am purser I ask the f/a's to start at the front of the cabin and I will pick up the slack later. If I am working in the back I just inform the purser I start at the front of Y and they can help out when they are available. IMO the service goes much better that way. Also if the other f/a is willing, they start at the last row of Y and we work towards each other, so pax see we are both working and trying to get drinks out.