In one box you can find at least

1 Brionac

2 Mist Wurm

or

1 Brionac

1 Mist Wurm

1 Catastor

Best pull was

2 Brionac

2 Mist Wurm

1 Catastor

so 3/5 of those sweet Synchros per Box (36 boosters)

in Walmart like packages (4 boosters) pull ratio seems to be 1 of those Synchros per package

(but some might have none)

best thing to do are:

get yourself a box from ebay / your local shop

buy the 3 single Synchros for the same price as a box on ebay

wait to trade for them they might lose price or gaing price it depends on future product avaiability