I have had a similar chart in my welding box since the 60s. I haven't refered to it in years, but kinda know what one to use now. Lenses are available from 2 to 16 and should be in every welders box. Using the same lens for every job just makes it harder to do a good job.
No responses to this post kinda tells me that our hobby and home welders arent getting quite enough education on the job at hand.