Hi @Arthur_Seiser ,
I believe the Easify Product Options app could be a great fit for your requirements 
:
Here’s my updated suggestion for your setup:
- Create a Lithograph (or Poster) product and set up Size options (e.g., 12x16’‘, 18x24’').
- Create a Frame product and set up Size options (e.g., 12x16, 18x24) and Glass Type options (Standard, Museum Glass). Then, specify prices for each type of glass with a specific size.
- Install the app and create an option set.
- Add the 1st Glass Type option for customers who select Lithograph size 12x16’'. Choose a suitable option display type, such as Image Swatches. Link your relevant products to those options. Enable Conditional logic so these options only show when customers select the variant 12x16 of the Lithograph product.
- Similarly, add the 2nd Glass Type option for customers who select Lithograph size 18x24’'.
- Finally, add the entire option set to your Lithograph product.
If there’s anything you don’t understand, let me know, or feel free to reach out to the Easify team via the in-app live chat for quick assistance.