Difference between feeding enough and overfeeding

Hey everyone,

Got another question for y’all, as a newbie that I am.

When bottle feeding two kittens, I can’t exactly measure how much the little ones are eating as compared to when I syringe fed them. This makes me quite paranoid.

How do I make sure I’m not over feeding them? Atlas and Calli are three days away from three weeks. What are signs that I could be overfeeding?

In addition to that, how does everyone else here do it? Do y’all just fill a bottle and let everyone have a turn or do you prepare multiple bottles to be able to measure a bit better?

Thanks for your time. Look forward to figuring this out with y’all!