Hello Jeffrey,
You could set it up like this:
1. Set General > Mode as Product quantity
2. Set General > Date range as Lifetime
3. Enable Limits > per product
4. Access the specific product page on admin and set the Limit per user option as 1
Regarding guest users, you have 3 choices:
1. Block all guest users from buying all products, regardless of the quantity.
To do that, you only need to :
1.1 Enable General > Guests > Block guests from buying products
1.2 Set Block method as All products
2. Block guests from buying specific products, regardless of the quantity.
To do that, you only need to:
2.1 Enable General > Guests > Block guests from buying products
2.2 Set Block method as According to limit options
2.3 Access the specific product page on admin and Enable Block guests
3. Block guests from buying according to limit options.
This will block guests from purchasing products beyond the limits. You’d need to:
3.1. Enable Guests > Do nothing but block guests from purchasing products beyond the limits
Let me know if it helps 😉