So... have the word "EOMA68" in the logo for both tiers, just have something that universally indicates "premium" or "certified" or "extra" or "plus" in the "EOMA68=Certified" logo, and have that something NOT be in the other logo. (A yellow or gold-colored award-ribbon symbol comes to mind, but that's just me.)
Luke, with all due respect, it's kind of obvious that you're not even trying here. This is super easy stuff. This is "grade school" easy. You should not be flunking art class over this!
...feck it. I've got to get ready for some errands, it's that day of the week. I'll draw up examples and show you, when I get back later. It'll be a few hours.