Thank you SO MUCH, everyone out there who took the time to comment and give me advise. Here are the results of the poll:
It was pretty close between the 3 designs for the back so I decided to just use them all. #2,3,6 were the winners for the front so I focused on revising those as per your suggestions.
Design A Focus: Editorial
A Back: (not sure yet whether I'm digging the red line around the text box.)
Design B Focus: Mix of Editorial and Gallery
Design C Focus: Gallery
C Front #1: (photos all angled the same way)
C Front #2: (Just to have a vertical option to go with the vertical front. The images are kinda repetetive since they're on the other two cards already.)
I took my return address out so I have the option of dropping them off at galleries, and I can just make sticky-labels with my address for the ones I want to mail. This way I can use the text area in the middle either for an address or for a personal message if I send a couple at a time in an envelope.
As Rory said, there are restrictions on what the post office will mail so I'll have to take these over and double check with them before I send the files to the printer. Though I remain hopeful... I did once mail a plastic knife, spoon, and fork with the address written on them in sharpie and they made it... almost a year later.
Again, any thoughts on these new versions? THANK YOU SO MUCH!!!