CB70 have a smaller floorspace than a 41q. Those are more recommended for people with arboreal animals that need the higher space.
You can upgrade to a 41q, but I think 32q are more suited for bps. They have a bit more headroom and are the perfect size.
Don't go from a 15q to a 41q. That'll shock them. Usually moving from a 15q to a 32q to a 41q is more suited.
BHB has awesome animals. You won't be disappointed.