I've been playing with extra resources ever since I got the game in November. Aside from Luxuries, and limits for icon graphics, I've had no problems. Both of these issues were dealt with in the latest patch however. Though like I said, it might be wise to leave the luxury changes to the end, just in case. Other than that, I'd say it's pretty safe to add whatever you want.
BTW, when I mentioned experimenting, what I had in mind was coming up with numbers that suited you, not what the game can handle. Making any changes to the default game is a purely subjective exercise, and IMO it's pointless using someone else's numbers as guides. All you need to get a start on that is the ones that are in the default game. If you're comfortable with those, then use them as the template for your own.