I just started experimenting with this a few weeks ago too, having ridden with zero forward lean since I started but having been encouraged to experiment with it a bit.
Anyway it seems like most manufacturers have a slightly different system to adjust the highbacks. On my Unions, I initially tried a setting of 3 (out of a possible 6). That was a bit too aggressive, so I dropped it back to 2 and that seemed pretty good. No idea what bindings you're rocking or how many degrees that equates to though sorry but I did find it gave me a bit more support on my turns on steep terrain.
Another technique thing to think about that might help (it helped me a lot) is to think about using your front knee to steer the turn on steeper terrain. That sort of forces you to bend your knees more.
Whatever you do, make sure it's the same on both bindings. I accidentally spent most of a day riding with my left leg at +3 forward lean and the right leg on 0... couldn't figure out why it felt like a dog had bitten my left calf until I checked the highbacks when I got home!