Issues with Lunchbox on irregular surface

Hello everyone!I have been trying to divide this polysrf into equal rectangles but the sides keep messing up. I’ve also tried splitting the polysrf into 3 separate surfaces but no luck. I essentially want to add panels to this surface and be able to adjust the size of the panels using the number sliders. Thanks in advance !!

image
Skin Dev.3dm (201.1 KB)
Skin Dev.gh (18.4 KB)