Hi Philip,
My user is in 'tty wheel usb input video' (among others).
that shoud suffice.You need to use '-keeptty' for xinit and preselect a TTY. For myself I have put this into my bashrc and it works quite well:
xinit ()
{
local VT;
local DISPLAY;
VT=vt$(tty | sed 's/.*tty//');
DISPLAY=:$(pgrep -cf 'X.*keeptty.*vt');
/usr/bin/xinit -- $DISPLAY -keeptty -wr $VT
}
Cheers
Björn

