Deduplication in APFS ?

Hello!

i have some duplicate files on my macbook now ( sshd / hfs+ / macos sierra).

i plan do fresh install to high sierra, when 10.13.1 releases - i plan

to reformat my sshd to APFS, make a fresh high sierra install, and then copy all my files back to new disk.

in that case, what is APFS behaviour with same files?

it authomatically do deduplication, and physically i have only one file of each version, with symlinks, or no?

also interesting, how i can in that way import my current Photos and iTunes content

thanks in advance!