changing h1 tags on different pages?

You’ll need to make some custom page templates for archive-product.php (category page) and title.php (product page) and maintain them ever after. Note that every page should have one H1 tag for search engine requirements.

However, these tags have very specific css classes, so putting in some custom css to change the appearance, or make them the same, would be an easier path. Can you be more specific about what you would like to achieve.