I'm not sure there's a simple answer for that question.
24 mains give you tokenization and multi-denomination, but no internal progressives.
20T mains give you tokenization and internal progressives (although I found a bug with the gamble feature when cashing out for partial credits)
22 & both versions of 23 mains are multi-denominational and support internal progressives (I think), but to use the progressives properly any game set up for them must be allocated to a single denomination only.
You need the later mains for the V7200 games.
You need specific older mains for the game "win pigs fly."
Personally, I settled on the 24 mains for most game setups and have chosen to sacrifice progressives for multi-denomination and tokenization. I don't own a V7200 so I'm not sure how these mains behave when you have a double bet deck.
My experience with graphics has been hit and miss. Some work better with certain mains than others (in general, newer graphics versions with newer mains), but then a particular game will come along and throw a monkey wrench into the mix.
Sorry I can't be of more help.
Stat