Ah, I see I made a little mistake. I have never heard of a "winsxs\Backup" folder and don't have such a folder myself, so I assumed you were talking about the "winsxs" folder. My previous answer was for "winsxs", not for "winsxs\Backup".
I don't know what kind of files the "winsxs\Backup" folder contains. The name would suggest a copy of other stuff, and that it will never be used. If that is the case then yes, it would be good to include this folder in the list of spacehogs.
So you can remove all the directories defined for SpaceHog, because they will be covered by the last month rule...
No. Many files will already be selected by the last month rule, but not all of them. The list of windows spacehogs folders is there to make sure that very infrequently used Windows files are still seen as spacehogs. Also, the list is a fallback in case the last-access times are not recorded (see LastAccessEnabled
for more information).