how do i light catchlights?

i have to shoot a student shortfilm in a couple of months (i am the student) my talent has to wear glasses and my story requires me to setup a catchlight for his eyes that gradually become brighter, in my storyboard he has to look almost directly at the camera or maybe like 20 degrees apart, its an ECU and im worried the glasses will reflect the catchlight and ruin the shot can i get some tips from veterans? (also if it wasnt obvious we are VERY low budget and will be using a portable 4 dollar bi color light with a lot of paper in front as diffusion)