[Just a small shake of his head as he notes it all down.]

Not at all. You could always start with a cheaper material like cork first to see how they go.

[.........Hm.]

The one thing about metal is that you would have to add that to the cleaning maintenance. Cork could have a benefit in that you could allow customers to take them with them, which would also serve as a form of advertise. Could offer special metal ones as additional merchandise or promotion.