Righty-O.
It all depends on what they start out with. Basic knowledge? IW goes invisible at the start of the fight, and McCulloch will never find her. Endless stalemate.
If he manages to find her one block away (which is very easy for him to do in a city) AND if she hasn't disappeared, he will take her out.
Here, he was able to search over the entire US continent (after being given a rough idea of where to search):
He could then trap her in the mirror world (it took Wally time to realise it was a fake world):
http://i.imgur.com/osO4YqE.png
Trapping her would def disorientate her:
http://i.imgur.com/uOVcnbF.png
Then he can mess with time, and turn her into an infant:
http://i.imgur.com/ykyLCMO.png
But yes, he has created clones to blanket an entire city:
http://i.imgur.com/9yXUDbB.png
And they can change appearance:
http://i.imgur.com/sgZrzRn.png
Of course, if Sue gets him, she can bubble his brain. But MM has the advantage over a block, if he then quickly sends himself away.