I really like Basilisk II, it's a great Mac emulator for 68030 and 68040 processors. One thing I've been trying to figure is how to have more than one instance of it running with different preferences. Basilisk II has two parts to it, one is the emulator (BasiliskII) itself and the other is the program used to set the preferences (BasiliskIIGUI). The problem (at least for me) is that the preference file and the pram file (named .basilisk_ii_prefs, .basilisk_ii_xpram) are stored in the user root folder. This means that even if you make a duplicate of the Basilisk II folder and make changes using the BasiliskIIGUI in one folder it will affect the changes in the other folder.
What prompted all this is that I wanted a version of Basilisk II running as a compact Mac with a resolution of 512x342 b&w and another as a color system running at 640 x 480. So I renamed my duplicate folder BasiliskII - Compact Mac to differentiate it.
After that it was time to dig into the apps using "Show Package Contents".
Big note: Me figuring this out was pure luck. I literally have no idea what I'm doing.
So after digging through the files in the BasiliskII and BasiliskIIGUI app, I found a reference to .basilisk_ii_prefs and basilisk_ii_xpram and changed them to .basilisk_cm_prefs and .basilisk_cm_xpram (cm for compact Mac).
Once I did that, I ran the "new" GUI app and set up the new machine and... ta da, two instances!
p.s. Just a little aside. Look at the Control Strip in the left hand screen. See its location? I wanted to move it to the bottom of the screen. Normally this would be accomplished by holding down the Option key and left-clicking on it with the mouse to drag it to the desired location. It turns there is a bug in Basilisk II. To get it to work you have to hold down the Option key and right-click to drag it.