Glad to hear. Most of the instructions seem correct. You need to run "Game.exe", not "Diablo II.exe", then multi-instance will work ;D.
The instructions for getting the renderer running on Linux are located here
. On my Linux system just a single prefix is fine. I actually keep the Diablo II folder outside of the prefix. The prefix is just to hold my registry settings in an isolated way from any other windows apps you're running on that machine. This also makes it easier for me to just open the d2 prefix settings file and modify the SavePath file if you want to do multiple versions. So basically on Linux I still have a Platforms and Saves folder just like Cactus, the only difference is that I have to manually copy the "Common Platform" files for the version I want to the root of my d2 folder, etc. At the end of the day the version switcher is just a glorified way to do all of these tasks automatically haha.
If you wanted to do multiple versions, I usually have:
/home/jon/Prefix/diablo_2 <--- wine prefix folder (we are using this for all the versions)
/home/jon/Games/Diablo II <--- root directory
/home/jon/Games/Diablo II/*.mpq <--- keep all of the MPQs here since they will be shared across platforms.
/home/jon/Games/Diablo II/D2.LNG <--- This stays here as well.
/home/jon/Games/Diablo II/Platforms <--- Platforms directory
/home/jon/Games/Diablo II/Platforms/[ddraw.ini, ddraw.dll, Shaders] <--- Just misc files that I'll also be copying when I switch platforms.
/home/jon/Games/Diablo II/Platforms/[1.00, 1.05b, 1.07, 1.08, 1.09b, 1.10] <-- Each folder has the Vanilla files (+ Singling if you are using it).
/home/jon/Games/Diablo II/Saves <- Saves directory
/home/jon/Games/Diablo II/Saves/[1.00, 1.05b, 1.07, 1.08, 1.09b, 1.10] <- Create a folder for each version you want to play.
So with this setup, if you wanna switch versions, all you gotta do is delete all of the files from the root directory but dont delete the Platforms folder, the MPQs, or the D2.LNG. If you don't care about copying the MPQs over, you could have a copy of those in the Platforms folder as well, and also the D2.LNG, so that way you really could just wipe everything (excluding Platforms) and then just copy all the platform files for the version you want, and copy all of the other misc files in the Platforms folder into the d2 root.
If you want to modify the ddraw settings, you just need to edit your master copy in the Platforms folder, and then replace the one in the d2 root.
Finally, you just need to open the registry and edit the SavePath so that it points to the saves dir for the version you want to play (character isolation).
At the end, the install should look like this (excluding the Cactus stuff).