My uncle’s fig tree produces 2 types.
What kind of tree is this? I've never experienced a fig tree like this one. First it grows small figs and then much larger ones.
I have never tried "it" but I have always heard that you can take a branch of an apple tree, graft it to (say a pear tree) pear tree and the Apple Brach will always bar Apples while the rest of it bars Pears.
Check out Grafting one tree to another. I think your answer lies there.