General question but does a product really require a position in _spree_products_taxons_ for any reason?

It's the order that they are displayed on the taxon pages (absent a different sort order being used.)

@Jared Norman I figured. Half the time its figuring out why something exists for core. So its safe to say you can have it be null or a duplicate number? I would think most stores are using other sorting methods such as new to old, price etc

Yeah, if you're not using the default sort, then it won't have any impact if there's garbage in there. That said, the "acts_as_list" code should ensure that within any given taxon the position numbers are unique and present, so you shouldn't end up with garbage unless your store has some code that's manually getting in there and inserting values.

Im trying to bypass using the admin and using a custom app that I can quickly tag taxons for products. ie. Just dropping in new rows into the _spree_products_taxons_ but since I dont know the position I just want null in there as its of no use to my front end