This doesn't work for me.
I have on /etc/conf.d/tigervnc
DISPLAYS="to:1"
VNC_OPTS="-depth 24 -geometry 1024x768"
And on /home/to/.vnc/xstartup
#!/bin/sh
XSESSION=Gnome
XDG_MENU_PREFIX=gnome-
#unset SESSION_MANAGER
#exec /etc/X11/xinit/xinitrc
#[ -x /etc/vnc/xstartup ] && exec /etc/vnc/xstartup ...