Matching wheel width to tire width

OK, so I have been reading and reading and…. you get the picture. So, I cannot find any discussions on what width wheels to match to x width tires. I don’t want to spend my hard earned $ on a poor setup… Basically, I’m looking at picking up a set of Maxxis Zilla’s either 28" or 30" (probably going to be the 30") and 9" wide front 11" wide rear. I have seen a few times that most people run 7" wide wheels all around, some run 6" up front and 8" rear and everything inbetween. What is actually the best setup for this configuration? Is there a rule of thumb like always get a rim 2" smaller then your tire? I like the idea of having the same size rim all the way around just for the purpose of being universal, but that’s about all I got… Also, I was considering running 11" wide tires all the way around, but that’s not going to work if I run the 30" tall tires, but I would like to plan for future setups too.