I'm pretty sure 411's 'spanwise flow' is a red herring in terms of stalling angle of sweptback wings...
Many variables at work, especially with early designs that needed wing fences and vortex generators for proper airflow control.
Boeing, at one time, produced a very nice discussion about all this, and might well be worth finding a copy....that is, if one were truly interested.
Or, one might travel to Arizona, and speak directly to a retired Boeing design engineer, who lives about a quarter mile from my present home...some enlightening listening...presuming of couse, if that desire to actually learn was still on the agenda....
