The squeaky noise is ok. We get that when Sam's sucking hard. You'll know the click when you hear it. If you are really worried about the teat being slow, you could always try her with a faster teat for one feed and see how she goes. We would get terrible refluxy problems if we changed Sam too soon - a lady in a pharmacy explained it as if they don't suck hard enough, a little valve doesn't open and let the milk into their stomach and it just pools...

You're doing a great job! Generally, when she's consistently finishing her bottles would be the time to offer more.

BW