The blend zone is very dark compared to the rest of the image

This is typically related to the edge blend gamma. It can be tweaked by following the instructions below;

• Open ScalableDesktop
• Navigate to the Edge Blending Panel
• Wait for the software to disengage the warp
• Set the gamma higher until the blend zone looks significantly less dark
• Click the Update Calibration button
• Navigate to the management tab
• Re-engage the warp.