NOTE: a custom modification of the netplay build will cause you to desunch if you attemp to play with someone using the default build. both players on netplay MUST have the same SD.raw
That said:
dolphin runs project m from a virtual SD (sd.raw) - you should be able to find this in the dolphin files easily enough.
you can make modifications to that file for a custom build of PM, this works the same as modding for a wii build.
gonna paste something from
SOJ
on the PM discord here for instruction you how to make changes to the sd.raw
"first download ImDisk
https://sourceforge.net/projects/imdisk-toolkit/ Navigate to your dolphin folder and find the sd.raw file you want to modify inside Dolphin/User/Wii/ Copy and paste to make a backup of that file Now after installing IMDisk, open it up and click on Mount new. Find the sd.raw you want to modify and make sure the settings match this
edited)
SourceForge
ImDisk Toolkit
Download ImDisk Toolkit for free. Ramdisk for Windows and mounting of image files. This tool will let you mount image files of hard drive, cd-rom or floppy, and create one or several ramdisks with various parameters. This all-in-one package includes the ImDisk Virtual Disk Dr...
double click on the drive and treat it like a normal SD card
when you're done, right click on the drive and click Eject"