I tried with the mod several times. I created party of 4 custom characters and set the number to party size max 6. After I got out of the tutorial, it wouldn't let me add anyone because you first have to, for some reason, dismiss a party member. Then it lets you add someone. But if you have party of 4 customs you can't dismiss anyone,. So I could only do 3 customs max of I wanted party of 6.
I haven't messed with mods yet, except getting freckles for my halfling, which is just a texture that replaced tattoos. Sounds like a simplistic mod that increases party size and that's it. But ya, sounds annoying and hoping dismissing customs gets fixed sooner than later.
