It depends. Use long haul as an example, the 777s have 3 different configurations and the 350s have 2. I'll leave the specific numbers to others who are much more knowledgeable than me.

In regards to the (occasional) slow service, it is a combination of lack of manpower and expertise. CX did add an extra crew member for certain routes in 2024, but it is still challenging for the crew. The crew was, and is still, very green. You only need 6 months of experience in EY to work in J. Some of us here have probably spent more time interacting with the iPads than the new BCs. Most of the time, I don't think it's the newbie's fault, but more of a testament to the structural problems of CX.