My curls used to get super stringy too... the trick for me at least, boils down to a few things.
I only brush my hair when it's soaking wet and has conditioner in it.
I co-wash, then I will put a different conditioner (a richer one than my co-wash one) while my hair is still soaking wet, and I leave it all in, no rinsing. Squeeze out extra moisture, step out, and apply gel.
Check my signature for products I use. I do have much shorter hair than you, so I don't know how much of a difference that will make.
type 3a/b, baby fine to medium, normal to high porosity except the canopy which is high.
recently chopped off about 4" - HOW LIBERATING!!! Learning to love my hair again instead of hating it for being a knotty mess.