[Jon Stratis]

It all depends on how much data you have going back and forth. How many data points per match? How big is each data point (in bits... Depends largely on the type of data)? What sort of extraneous information is passed back and forth (for example, if it utilizes an XML structure to transfer data, you have to account for all the text that makes up that structure)?

Honestly, the best way to determine this is to probably measure a small sample. Set up a proxy to send everything through that you can use to measure transfer size, then run through a dozen sample matches (all over WiFi). You should be able to figure out how much data per match per tablet is used, then calculate how much you would use for an entire event based on event size and anticipated number of matches.