While I am not familiar with Magento specifically; principal concepts of on-page optimization should hold true.
I wouldn't worry about an exact match (and whether or not someone is going to query that exact term) in your H1 tags, rather, keep your keywords toward the front and even include variants of the page title tag. Similar to the meta description, the H1 no longer contributes a strong search ranking signal, but should definitely be utilized in structuring taxonomies of information on the site.
For example, if those tabs fall below an H2 or H3 on your page, I wouldn't place the H1 in that position. As a matter fact, I wouldn't place the H1 there, period. As you know, the H1 is meant to be used as a heading tag and to provide a weighted emphasis to content that is to follow. Stick to using the H1 as it was intended to be used and produce copy for your audience.
Perhaps you could have your developer remove the H1 from wrapping your category or product, and instead, parse a configurable H1 attribute as the first line when viewing the information contained "Product Details" tab.
Just an idea...