Using a caliper to measure both the holes and the smallest drill bit that would fit through the anti-suction holes of my large Lunette, they seem to be 1.5mm. If my math is correct, that is just a hair bigger than 3/64 of an inch.
Are you brave enough to drill the holes on your cups to match?
Many of you have complained that the pinholes on your cups are too small and too low. "Turbo suction."