I feel ya, I also struggle blending this properly with shading and multiple light sources. The lesson is worth it though, and as you do it multiple times it gets a little easier every time.
That's actually one of the reasons I moved from gradient maps to manual blending for now, as it was easier for me to add terminators manually.
I'm still learning though, so I'm thinking of using gradient maps as a base followed by manual blending on top of it. We'll see how that goes.
Piece is coming along great man, it looks a lot more alive with the different light and shading effects.
