If you have the need to set your product with a single pre-designed template to a specific variant of your product and you want to prevent your customers from associating a pre-designed template with an unexpected variant, is possible via the pre-designed template settings.
Example
Below you can see how while changing the variant the pre-designed template is automatically associated, how you have set it in your back-office
How to do
Go on Tools > Pre-designed templates, you will see the pre-designed templates available for each variant:
In this case, your customers will be able to change the pre-designed template from "80x60" to "20x20" also are on the variant "80x60".
So you should click on the button, you will see the
button and will be possible to uncheck the flag "All variants".
Now is possible to select the specific variant. (see below)
Once selected the specific variant you can do this procedure for each pre-designed, and the result will be that your customers select the variant that they want and the pre-designed template will be assigned automatically.
So you will see the customizer screen without the button.