From this thread, I learned that rebounding is a waste of money on guards, and that rebounding for guards can be good depending on what you want to do. Got it, it's clear now!
I once had a guard who never got any any rebounds, even though his RB was I think a 5. He might have been able to get some rebounds if I'd actually played him in a game. I did some data analysis and was able to demonstrate that this was true, even though it took me about 16 minutes to set up the model and extrapolate the data from the dog that was eating my homework.
Don't ask what sort of Chunks they are, you probably don't want to know. Blowing Chunks since Season 4!