Installing e.g. Skyrim using already downloaded gog installation files possible?

I am running a dual-boot PC with Windows and Linux MX. I have installed Skyrim from gog-files on Windows. I recently learned about Lutris, and I was happy to be able to play games without to be forced to use Windows.
First I tried to run Skyrim via WINE from the Windows installation. It started a new game, seemed to run normal - with every sounds but the voices. This wasn’t satisfying.
the skyrim folder on the Windows partition has 27 GB, free space more than 40 GB. So I tried to install Skyrim via Lutris on this partition, but Lutris said the game will not work on a Windows-formatted partition. So I freed 60 GB on a Linux partition and started the installation via Lutris using my gog account. Lutris wants or better say needs to download the 24 GB Skyrim-Installation flies. This would take 6-7 hours, and Lutris does not ask where to store this downloads, it uses automatically the home partition, on which I only can provide 10 GB free space.
So I am looking for a method to make Lutris use this already downloaded installation files. Is it possible, or has someone to modify Lutris to let there be a choice between installing via download or existing files?
Thanks for any help