I dont think R.GIGGS would want the club to retire the shirt ,hes far to modest for that ,we all know how respected GIGGS is as a person and a footballer,there should be another way of celebrating ,the achievements of GIGGS .
The number 11 will always be an iconic no ,Best WORE it as well ,along with no 7 ..
Whoever wears the 11 shirt when GIGGS retire ,has big boots to fill but that should be the challenge for that player??
I would suggest that may be name a stand after him along with a statue ...that would be a longer lasting memory rather than ,retireing the shirt.