Rear view mirror compatibility for Custom

[onyxx]

Hi Everyone! Just a quick question. Which rear view mirror is suitable for Transit Custom? I only need the arm, as I want to make a mobile phone holder. I want a factory arm up on the windscreen, and somehow fit my phone holder at the other end. I think it would be a good height to have my phone up there. Would be visible, out the way, and probably a bit more shaded than right above the dash. My phone overheating in the direct sunlight over a long period of driving in the summer heat. Any good ideas greatly appreciated. Thanks in advance. T