With my home tomatoes I have had the Blossom End Rot problems as well, mainly with plants in big pots, and with heirloom. I agree that it is just a passing issue. Would like to see a picture of your shading process. I agree with you on the hot temps and maters don't get along.
Sounds like you'll have a nice bunch of pumpkins in the fall. I planted a patch last year and had a nice harvest. What variety did you plant?Also planted 14 rows 190' each of pumpkin this weekend and had a good rain early this morning.