Vern,
Way back when, (early 1990's) I ordered a Petite Negri. Seems like I must have just had it in a pot. I knew nothing, absolutely nothing about fig tree growing. Job change meant moving out of state. The little fig tree and some precious flowers moved to town to my Mother's home in SW Missouri, zone 6a. It grew like crazy, planted against the South foundation under a wide overhang of the house. But the fruit never got ripe - at least if it did, we didn't know it. :-)
One time when we went back for a visit, it was gone. Mother had chopped it out, she hated it. No fruit, taking over her flower bed, it was a nuisance. :-( Of course, I didn't even know I could have saved a cutting or two for future use.
So, judging by how it grew in a location three zones cooler, your Petite Negri should do okay in zone 7b and maybe you will even get ripe fruit! lol
Elizabeth, zone 5b