Small or large tube diameter?

Hi

I'm thinking of buying a new rigid chastity device, probably the modular model 11.

The measuring advice on there says:

I suggest you to choose short and wide device. If your flaccid penis is 1" or 25 mm thick - choose cage 37 mm. For bigger sizes - choose 47 mm. Open design will prevent oedema, sweating or irritation. Large diameter will help your penis dry and clean.

This is very different to what I currently have, which is a tube that is roughly with diameter of my flaccid penis.

If I were to follow this advice then I'd get a tube diameter about 1cm larger.

It also goes against general advice elsewhere, which says that you shouldn't have space to grow. Such advice is summarized on house of denial:

Ideally you should fill as much of the cage as possible so that it fits like a glove. You don’t want to give yourself too much (if any) room for your cock to expand or grow into the cage, so have this in mind when making your selection.

So, my question is:

Does anyone have a large tube diameter and is it beneficial?

Any other thoughts?