Hello Magnificco!
Yes, we are growing, and testing cold hardy figs here in middle europe with Gelu.
The main harvest season depends of your variety, there are some earlier ripenning varieties like Ronde de bordeaux, or Mitchurinska whiches are sarting to ripen in the first decade of August, but the major harvest starts at the end of august, and early september, if a variety ripens later than this season usually dont producing valuable fruit due to the few sunshine.
I have 3 unknown variety, they are doing fine, but they are too late ripenning. Next year, I will plant out some hardier cultivars and we will see the results.
If you have any other question, just pm me!