Concerns with Materials

On visiting the Student Union again, I noticed that the ceiling of the room I intend to hold my installation is made from a polystyrene type material and so using 'white tac' to hold up each individual strip as originally planned will no longer be suitable as it would not hold. And so now I am un sure of what material to use...I could use something called 'adesive dots' which is a clear sticky form of blu tac although as I would need 2000 of these, it would be too expensive but if using drawing pins to hold up the paper doesn't work well in the material or look particularly great as a whole I will most probably just pay the price as it is definitely the best option.