Reduce the OS after installed.
In the quote of first Post there is a comment about WinSxS_Reduce_Trusted this is a tool made by wimb based on cdob commands, what it does is reduce the content of Windows\WinSxS folder, during some test ran on 10x64 Compact LZX installed and using cdob commands got a reduction of about 0.85 GB of used size by the OS, (only valid for 10).
Comparing LZX and LZX Reduced there is a saving of 0.85 GB, lets say almost 1 GB
I also mentioned the OS can also be reduced if we edit the WimBootCompress.ini [ExclusionList], but this requires to capture and reinstall it, this apply from 7 to 10.
In fact our current modified WimBootCompress.ini [ExclusionList] section already contains this two lines to reduce the used size comsumed.
\MSOCache\* >>> This is from MS Office installation, usually from 250 MB to about 1 Gb depending of the program version.
\Recovery\* >>> This is 165 MB on 7 and about 420 MB on 10.
So far all reductions/deletions are safe and do not remove any critical characteristic of the OSs.
Of course there may be other files/folders that could be added to WimBootCompress.ini [ExclusionList] but as also said on the quote on first Post:
Then any files/folders added by the user to [ExclusionList] section will not be included on the new WIM file (no matter the consequences), edit it wisely to avoid future troubles after apply the new WIM on a new installation.
In fact it is as a chopping by brute force.
I invite all readers of this topic to share their experiences when chopping the OS.