Setting the screen resolution for a headless VNC connection on a Raspberry pi:

INSTALL X11 VNC AND SET PASSWORD:
sudo apt-get install x11vnc
x11vnc -storepasswd

SET PARAMETERS:
nano ~/.xsessionrc
    # Start X11VNC
    x11vnc -bg -nevershared -forever -tightfilexfer -usepw -display :0
output (CTRL-O) and exit (CTRL-X)
chmod 775 ~/.xsessionrc

SET SCREEN CONFIGURATION:
sudo nano /boot/config.txt
    hdmi_force_hotplug=1
    hdmi_group=2

***MODES***
hdmi_mode=9    800x600      60 Hz
hdmi_mode=16  1024x768    60 Hz (SVGA)
hdmi_mode=69  1920x1200  60 Hz (Nexus 7)
hdmi_mode=82  1920x1080  60 Hz (1080p)
hdmi_mode=85  1280x720    60 Hz (720p)

****EXAMPLE****
# uncomment if hdmi display is not detected and composite is being output
hdmi_force_hotplug=1
# uncomment to force a specific HDMI mode (this will force VGA)
hdmi_group=2
hdmi_mode=16

REBOOT:
sudo reboot

TA-DA!