The Groundhogg WooCommerce integration by default will tag the Contact with a tag for the base product, but tagging variations is not possible in the existing extension.
We have solved this issue…updating variation tags on Contacts for past orders, and tagging on new orders as well.
We also have some ancillary code to generate the MySQL insert statements for the Content Restriction (tags on posts), and WooTags (applying Tags to be added to Products).
We are modifying and updating the Force Login plugin to assist in enforcing the Logged In condition in the Content Restriction plugin.
Get in touch if you need this solution, we can have it ready with you in a couple of business days.