Your way of generating boosters seems a bit complicated- I would do it like this:
I`d use the following site:
http://magiccards.info/search.htmlUnder options i`d mark: View as checklist
Then i`d specify the colours, rarity, etc. and start the search.
Now there is a checklist- You could now use an simple random number generator to get your card.
Maybe we could generate the boosters ourselves? E.g Two guys start an apprentice "game" open the magiccards.info site, create their checklist and then they generate the random numbers with the "roll a x sided die" function of apprentice.
Since those two would be opponents in the tournament i don`t think that there would be any cheating.