Recovery of bitcoin wallet after having re-written on the disk

[KG17]

Hello everyone I recently came across an old hdd that was having a few bitcoin in it from 2011. The issue is that the hard drive have been partially re-written with a new windows and other datas. I already carefully make a copy of the hard drive to .img file. I already tried the "classical" way of recover the file (recuva, R-studio) ... and they didn't find the wallet.dat (they find other .dat but some from windows).
Even if i know that the chances are low that my wallet or at least the private key is still on this hdd i would like to be 100% there is nothing left. After having search i have seen that we can use pywallet --recov mode to do that and also an hex editor to search for the string but there is a few issue :

-When I launch pywallet --recov he ask me for the passphrase of the wallet but i'm totally unsure about the passphrase, would it affect the recovery if I put a wrong passphrase ?

-When i go for the search using an Hexeditor and searching for the sequences (as described there https://bitcointalk.org/index.php
topic=1983382.msg19785384#msg19785384) the hexEditor crashes probably because the .img file is around 300 Go any way to avoid that ?
-Is there any other way to recover that i didn't thought of ?

Thank you all in advance and have a great day. 

[nc50lc]

After having search on the web for a few hours i don't really find what are those "42 number of 12 digits in ascending order".

Yeah, AFAIK it's never been documented but you can try to ask the owner himself: Pywallet 2.2: manage your wallet [Update required]
He's active 'till last year.

Anyways, the "pywallet_partial_recovery_nnn.json" file is less important than the "recovered_wallet.dat" file in the same directory.
That should be ready to be imported to Bitcoin Core and comes with the passphrase that you've set in --recov.