We first identify the stagnation point that forms for a blocker of radius 5R. At this specific point on the z axis, the net flux of substrate in the absence of other particles cancels out, giving zero velocity for a test particle. Since we examine solutions in the steady state, we place a second, consuming BMC at the point where its position will not change with time. Unlike the test particle considered in earlier sections, this second BMC is assigned a finite, variable radius (e.g., R, 2R, etc.) in order to capture additional surface effects that may arise from realistic BMC sizes. The setup is shown in Figure . With both the central blocker (radius 5R) and the second BMC (at the stagnation point, with explicit radius) now present, we introduce a test particle to measure how the local gradients and flows are altered. We sample the test particle's velocity at various positions along the z axis, ranging from well upstream of the blocker (close to the background source) to well downstream. As the second BMC's radius increases, its surface further distorts the substrate distribution originally shaped by the blocker. By comparing test-particle velocities across these different radii, we can quantify how an explicitly sized BMC modifies the competing gradients in a consumption-driven environment.