Hi Ryan, and thanks a lot for your help so far!
I tried using the 1Dto2DIndex function, and I am having a hard time getting it to work for my specific needs. I’m also a little confused about this statement:
“Then when vertex painting the meshes, you just paint the first one as 0/TotalTiles, the second one as 1/TotalTiles, third as 2/TotalTiles and so on”
What do you mean by that? Is it how I get the correct grayscale value with which to paint the vertex color? I attached a few images of my setup explaining in more details what I need to do. If you wouldn’t mind taking a quick look to see if I’m on the right track or not, would really appreciate it 
Thanks again!
