As a former Indcar fabricator & TIG weldor, I have to say Auto Darkening Helmet lenses are horrible. They don't react at the same speed as your eyes.
I've been using a #10(dark) lens, with Gold layer, for 40 years and your eyes need to adjust when you light the arc.
You can buy magnifying lenses to go inside the helmet, uses same lens set up you can get on headband mount, and come in different strengths, like reading glasses.