I think most of monitors are 7" and 6.2".
For Toyota Mark X, I have no idea for the special, I just have Camry, COROLLA-EX, Land Cruiser, Vitz, Vios, Aversis, 05 Para Hilux, 09 Hulix SW4,*Majority, Prado 4500, old Rav4, Crown, FLORID, COWRY, COOLBEAR, etc.,
But you can take universal model into consideration, if needed, email me, I can give you some suggestion.