Have you tested welders before? For a company or otherwise? That may help me better answer your questions. What is your experience related to the topic? If you have no experience in the matter, I suggest working with someone who does. The CWI credential does not reflect an aptitude or ability for anything. In many cases, its just a certification that one passed a test on a given day.
I passed HS English and have even been using the language my entire life, however, I have no knowledge of diagramming a sentence and wouldn't know a dangling modifier if I ran into it. Though I use the language and am around it, I am by no means qualified to "inspect" others use of the language and tell them if it "complies".
There are a couple of concepts you can consider.
1) A facility fully equipped and available for an organization to perform large-scale testing.
You could charge "rental" for the space and equipment, and then have add-ons for arranging/performing inspection and testing of completed welds.
This will take a considerable amount of equipment investment.
2) A facility that charges "by the test".
With this option, your initial investment for equipment can be low. Understanding that most decent employers perform their own testing is worth considering. If you build a good relationship with them as an organization that can test people in a manner that meets their requirements, where codes allow, you could perform the testing for them.
Do not think "Build it and they will come!!!!"
I have helped a couple of AWS ATF's get started but not all function well due to the fact that they are schools and other than "free money" from grants, they are limited in resources as far as people who have experience in industry testing welders. Many instructors are "single industry" experienced and may not have ever looked at a code.
Realize this, business and industry will often indicate they would "like" some type of service or resource in the region. This "LIKE" does NOT mean they will use it or support it.
If you are going to test individuals or even people for a company (not advised unless they have a WPS but just my opinion), you will need WPS's. Sure D1.1 and a few other codes allow for "prequalified" WPS's. But other codes do not. So knowing the "need" in the region can help you prepare for what code books you want to buy.
I have been working on a website for gathering and sharing knowledge related to the subject but have yet to get anything complete. I am intending to move forward a little quicker on the subject. The site is weldingclassroom.org and there is a registration form at https://wp.me/P8Uwjj-3b
. I only have a few pcs of content related to setting up a test facility but your welcome to look around.