I worked for a plant that manufactured automobile frames. Tests for welders were on actual parts, actual conditions. This plant didn't require code compliance, the actual welding was nothing like pipeline or structural work. This was sub assembly and  assembly line MIG welding, no prep work, one chance and done. There was drug testing 20 years ago, and by 15 years ago hiring was done through Pensylvania Job Services, or what most call the UN Employment office. I think this was supposed to establish  fair acess to everyone in a plant where nepitism was the old standard. You are wise to learn all You can about the welding required for Your products, Not only do You need to know good from bad, but You will need to know how to estasblish proper parameters and procedures for the work, and train welders if You can't hire people with sufficient skills. Perhaps You need to hire someone in this capacity.