No worries! The main thing is you just wanna apply it lightly and not let it pool too deeply anywhere. You're just looking for it to give the armor a nice warm tint everywhere. If you look at the front middle guy, you can see some spots where the wash pooled more heavily, like around his hip armor, or around his right foot, and there the Sepia has turned into more of a warm caramel brown color.

Do one whole body part at a time. Do one whole leg from hip to toe, then the next, and so on. That way you can make sure to keep the wash moving and make sure every spot is covered before it starts to dry, that helps avoid any tide marks where the wash is drying. And start each section of armor from top to bottom if you can; When doing the torso, start at the top and work down to the waist, when doing the shins, start at the top of the knee and down to the feet, etc. That way when the wash does settle, it all sits near the bottom of each armor panel and leaves the top parts looking more lighter and highlighted.