My experience with several batches this winter produced much the same result-- definite fermentation, even a hint of the ammonia smell. but the finished product lacked really sticky threads

I'm too far North for figs, but we have mint galore. Will give your technique a try this summer.

Till then, I'll just use commercial natto spores bought from an entity our host calls the "big slimy river." ;-)

*Ochre Harebrained Curmudgeon*