Is there a trick to make suction cups more sticking?
When mounting suction cups on glass, tile or ceramic, a little water or liquid soap seems to help them have a good bond. I don’t know if your desk top is wood..so I’m guessing that it is, because of dents and scratches… so, water or liquid soap would eventually damage the wood finish from the moisture… My next thought would be to try rubbing the surface of the suction cup with a tiny bit of cooking oil and see if it holds firmly for you. If not, the dents are probably allowing air to enter between the suction cup and your desk top, breaking the seal. You could sand and refinish the desk top…to eliminate the dents…or… Buy a piece of heavy duty glass with little rubber, skid proof discs…put the glass atop the desk and then, the suction cups on your flight system will adhere to the glass.