Transitioning to sleep sack

Hello,

i am wanting to transition to a sleep sack (different brand) and use the breathing band on top. I had a question about this because I know you're not supposed to use pattern sheets as it can interfere with the breathing tracking. Does the sleep sack AND pajamas also need to be solid or it doesn't matter?

also, what tog of sleep sack do you recommend under the nanit breathing band? Wondering what everyone has had success with.