Of the varieties that I grow every year the worst one to get sun scald is Red Barn. Whenever a large fruit doesn't have adequate leaf cover this time of the year on RB it usually gets scalded. Even though I do single stem lean and lower I rarely have many fruits get scalded and we just had two weeks with 100 plus days in a row and only had one badly scalded fruit. I use the Missouri pruning method on most of my plants to give them more coverage but it doesn't always work out. Sometimes when diseases or pests cause the lose of a lot of leaves it is a terrible problem down here.
A couple of years ago during a particularly bad infestation of spider mites I used DE, soapy water and Permethrin to help control them. I lost a lot of leaves and used a really heavy dose of DE in the mix and it left all my fruit with a nice ghostly white coating which seemed to help a great deal with sun scald which should have been bad with all the leaves missing from the spider mite damage. I haven't tried using the coating since but if I do loose a lot of leaves again from any of the many maladies that can hit a tomato patch I am going to try it and see if it really works to protect the fruits from scald. Of course I will leave out the Permethrin unless I am dealing with spider mites again.
Bill