Haha, thanks @Nicky! You gave me a few search terms and one of the top Google search results was this page:
So I used the formula that @MeEasy posted on that thread (thank you!), and I then found this guy who did a really, really great review of the exact light that I’m using in my setup:
I hope I don’t get in trouble for posting these links, I promise I’m not trying to sell anything or cause trouble, I really am all about Open Source Information 
That being said, I took the measurements from these two locations and then made rough calculations based on this information. My tent is 2x4, so, these measurements are only rough… At 2 feet, I’m getting 750 PPFD, @ 3 feet it’s 515 and @ 4 feet it’s almost 450 PPFD… this would still mean an average of about 570 PPFD.
Granted, this is at 100% of the capacity of the light, so taking 50% just to overestimate (I’m running my light at about 60%), which is an average of about 285 PPFD, which would be 20 DLI, at my current settings, which is low, according to this site:
Photone - Grow Light Meter
Based on that calculator and that YouTube analysis of the light, I could do a couple of things… I just raised my light because I thought it was too close, so I’m going to drop it back to 18 inches, keeping it at 60%, and also add another hour of light to my schedule which would make it 20/4. That should raise the PPFD closer to about 420 and make the DLI closer to 30, as you can see here:
Thanks everyone for the help on this!!! This really is a great community! 
