I don't know the exact stack percentage for the 3 of coins but I have just used about 12 thinking since it's stackable it would give me a better chance than using one... much to my expectations I get nothing. Haven't gotten a single exotic from a three of coins in about a week straight of using... on top of that my rewards or lack thereof for after a match of atleast a 1.5 or better kd or a strike I mean I did 10 strikes in a row and all 8 out of ten dropped blues... atleast every other match or mission reward I don't get anything at all... and I wouldn't be complaining if I hadn't payed around $160 or more on this game between preorder year 1 to season pass to buying a collectors edition because I cldnt find a ttk standalone to buying another collector's edition for the xb1... and now RoI preorder. I just don't understand why I'm getting absolutely nothing for the majority of anything I do... RnG my booty...