IMO, though they will be competitive every game, realistically the best a 70 card deck could do at nats would be 6 wins. There's just too many variables that would lead to their demise. Some games would be time out wins, some would be ties, but 6 full wins would be the most I could see them doing.
Now next year, if and when dominant cap goes in, 70 carders will be more like 7 wins.