Answer:
"Wiggle room has been continually challenged by wriggle room, which has the advantage of alliteration. However, wriggle (from Old English wrigian, root of awry) means "to squirm, writhe, move sinuously," as distinct from wiggle, which denotes back-and-forth motion, not necessarily twisting." [source:http://www.taipeitimes.com/News/editorials/archives/2004/12/05/2003213862]
"Wiggle" room is much more correct to use the "wriggle" room, as it means you have flexibility to adapt your strategy while still maintaining the same direction. Wriggle room would also allow you to abandon one strategy in favour of another, even opposite, one.
Most of the time, what folks try to imply is closer to "wiggle" than "wriggle"