Allow customers to order a product in specific quantities only
Is it possible to force customers to order specific quantities of a product? I'm sure this could be done in 4.x although I never tried it myself, but I can't find any way to do it in 5.x.
For example, I want to offer one of my products in quantities of 32, 64, 96, 128, and 250. I would prefer not to make the quantity an option/variant (eg, 'pack size'), as I think there will be far too many variants this way.
The product in question has 6 base styles and two print options. Each style is priced individually, and there is a per-unit price uplift on one of the print options (the price uplift is the same regardless of the base style).
I admit that my products are usually configured in a very basic way and I try to have only few variants. There are probably some simple ways to achieve what I want. I just don't know what they are!