Since most gas diffusion is through the stem scar of tomatoes, you can modify tomato ripening by blocking the stem scar with wax and therefore you should consider this in any waxing treatment of tomatoes.   The difficult thing with waxing treatments will be to achieve uniform coating of the wax on the fruit surface.  In commercial operations in California, our mature-green tomatoes are typically waxed with a paraffin-edible oil mix that is applied by soft brush rollers.  In the lab we have done some application of FreshSeal on tomatoes and are using a small roller system.  Although this system is electric, you could improvise a hand cranked roller system and would only need to 2 brushes so that the fruit are rolled between the 2 brushes for a defined period.   The wax can be applied to the brushes from a nozzle or if thick, can be dripped onto the brushes. --Marita Cantwell