I have not but looking at their website, it looks like they are using bio-feedstocks for their lubricants and are focusing on sustainability and minimizing environmental impacts. From what I can tell, they meet API requirements so I'd have no qualms about using it. In the past I've used "G-Oil" (https://www.getg.com/G-OIL.php
) which is a bio-derived oil made from was beef tallow. It was a little pricy but never had any issues with it and liked the idea of using a non-petroleum derived product, problem is I can't find it in stores anymore, I'm guessing Hydrotex may be using a similar feedstock/process to make their products.
If you really want to go down the rabbit hole, you could look at "Bob is the Oil Guy" and see if anybody has run Virgin Oil Analysis (VOA) and/or Used Oil Analysis (UOA). If you can afford it, I'd say go for it, just keep in mind the cheapest oil you can find today is still likely light years ahead of what they used originally (notable exception for high lift tappet cam setups which like higher Zn additive levels than standard motor oils today).