How do you prevent condensation of the front pane of glass?
Venting - either some sort of screened off vent or via computer fan.
Air being sucked out or blown in?
I have both in my viv. I have 3 small vents in the bottom front and 2 big vents in the top back. Air is drawn in from the fronts passes the glass and vents out the back. My fans only run when the lights are on. I let the humidity
You basically just want air movement across the front pane. I would think in would work better because the air you draw in is less humid but i have no scientific evidence to back that up.
Look around the site, do google searches, this topic has been covered.