www.radar.ch is a good spot to check out where the cameras might be. Before the journey.
The A3 must be having a fundraiser for the Christmas party; you're mad to go anything over about 87 in those 80-tunnels
On the bright side, your speedo will over-read and they will give you 5% off. So 120 works out to be 100-105 or ~180 francs (my guess)
The red flash is an infrared flash IIRC...