Nose Mask Design 3D CAD Design

I want to design a nose mask that fits inside the nose. I have CT scans of noses that have different highlighted regions. I was thinking to model the inside of the nose, that we would isolate the empty space inside the nose and then hollow out the inside of that so air can flow through. Then, attach each nostril with a piece in the middle that goes from the outside of the left nostril to the right. Up for other ideas too. I have a picture below of a rough idea, but as you can see the part that goes inside the nose is cylindrical here and not of a CT scan. I would like to average the CT scans to get an average of the inside of the nose and make a small, medium, and large size for the nose mask. I would want to make a mould too that I can print out with a 3d resin printer.