Hi Armando,
Well, what is your goal with your collection ?
Collecting and raising trees ? then replace the black Greek .
Having lots of figs to eat ? then as long as other strains are providing you the quantity, you're done ...
Having different strains, could help you have a longer season with ripe figs, which regardless of the color,taste... would IMO be a good thing .
But ok, available space is a greater criteria as trees need space to thrive ...
So it is up to you (and every one) to find the balance ... ( Buy some land ? Aaron is in Cali I think ? ... Ask Aaron for a stripe of land in his project , but don't tell that I've given you the idea , I would deny )