Hey guy's

First some good news: i've got my first BP switched from live to FT , hope the next one will also follow but she is really stubborn

But leaves the question:
I've read that rats are much more nutriciant for BP's then mice, is this true?
If so then i'd want my baby pastel switched over as soon as possible, because everybody knows: health and size matters
But my lack of experience leaves me with this: wich size rat is just a bit bigger than an adult mouse?

The BP i'm talking about now weighs about 223g, do you guys think its to soon to switch or it's good to switch?
When do you switch??

Thnx in advance