First, congratulations on your process for helping protect those that depend on safe, reliable gluten-free foods for medical reasons!
You are correct that both manufacturers, brand owners and consumers have every right to be confused by all the various claims around certification and the associated symbols, on packaging. To our knowledge, all gluten free certification claims around the globe are dependent on testing results, some using various approaches with manufacturers to gain assurance before granting permissions to use their trademarks/seals. Some schemes use remote questionnaires, some claim to conduct an on-site inspection from questionable experienced food safety professionals. As we all should know you cannot test your way to producing a reliable gluten-free product. Testing at the very best of times, requires professional analysis methodologies and techniques can be unreliable. I know i am somewhat bias, but I do believe and know that the Gluten-Free Certification Program (GFCP) www.glutenfreecert.com provides consumers with the most consistent and preventative food safety assurances possible, when a manufacturer/brand makes a gluten-free product claim on their label.
I also know that the GFCP is the only GF certification program annually verifying and certifying the manufacturing facility and it's gluten control process, for their ongoing control of any gluten or cross-contamination in their facility. This process is annually audited by over 15 globally situated ISO 17021-1 and ISO 17065 accredited certification bodies, who collectively employ over 300 certified GFSI food safety auditors, that are all additionally trained/certified in the robust GFCP Standards & Policies. This provides a true ISO based unbiased and arms-length certification process, which compliments any other similar third-party food safety system audit to mitigate the risk of a gluten-free product failure.
So in a nutshell, GFCP focusses first delivering the most rigorous gluten-free manufacturing assurances in the industry, followed by options for brands to market their GF products, with the endorsements from leading celiac organizations in North America and around the world.