When there is only one variant I want my custom fields to be equal in template and variant itself. What I tried is overriding write and create methods in product_template and setting there needed values in product_product.

This approach is working fine. The problem is when I override the same methods in product_product. Odoo crashes because of endless recursion. I understand why but don't know how to fix it. Maybe somebody could hive me some clues?

Or is this approach bad by itself?

I see the needed functionality in weight field - it updates in both ways. But I don't quite understand how it is done because I am quite new to python and odoo.

Thank you for your time.