how to add the new chop data suit with the original sop data

hi, nice to meet you .i was so confused when I learn about the pixel mapping on Mathew tutorial. and hope someone can help me.
when I chop to the Sop box and merge the data with the data from circle feedback, I found the circle feedback data is not the same can I change it .
and how wahts the meaning of the data length .how it accord and how i change it .
i will be so glad if someone can help me.
thankyou a lot
pixelMappinglesson2.3.toe (7.49 KB)
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屏幕快照 2018-12-31 上午8.15.36.png

Could you point me to the link for the Matthew Ragan tutorial. I checked the file and you are merging 2 completely different things so they will have different lengths, so I want to see that you are attempting to achieve in the video.