Max size = the maximum size of the archive to scan. The default is 1MB
Max number of files = How many files inside the archive to scan. The default is 10.
Max recursion depth = How many
archives deep should I go. The default is 1.
Note: These default values are for the active protection, not for the on-demand scan.
It is a personal preference in my opinion. To be executed, a file inside an archive needs to be extracted, so even if it is buried 10 archives deep (it rarely happens, if you ask me to have a file inside an archive, inside another archive, inside another archive...10 times) it will be scanned before execution. If you have resources to spare (mainly a powerful multicore CPU), go ahead and change it. But I would rather increase the size of the archive to scan a little bit - maybe 5MB (5120 kilobytes). You will probably notice the impact on your system performance when downloading archives (including packed installers) from the Internet.
From the
manual:
Max. recursion depth
When scanning archives, the Realtime Protection uses a recursive scan: Archives in
archives are also unpacked and scanned for viruses and unwanted programs. You can
define the recursion depth. The default value for the recursion depth is 1 and is
recommended: all files that are directly located in the main archive are scanned.
Max. number of files
When scanning archives, you can restrict the scan to a maximum number of files in
the archive. The default value for the maximum number of files to be scanned is 10
and is recommended.
Max. size (KB)
When scanning archives, you can restrict the scan to a maximum archive size to be
unpacked. The standard value of 1000 KB is recommended.