I always protect my leader, i am afraid that if i follow a weaker mate the teammate will be too weak and cant follow the peleton

This is a very good question. I think protection saves the protected rider a lot. But if I want to keep a good rider close to the front to try to join a break, I will have him follow someone I have pulling up front. This is when your question comes to mind. My answer comes from looking at the heartbeat of my following rider, which shows whether he is working harder than teammates back in the peleton, or less hard.

What about pushing? Put your leader to follow a teammate, or just push with your leader and protect with your teammate?
I guess they're equally efficient, but if anyone test and came with a different result...