FLOWIFY will not impose a grid on my rectangle. PLEASE HELP

Extensions
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Attaching file here. I have all of them as groups and I am trying to imply a grid. It just will not work i have tried no less than 15 times. Is there too much geometry in my stair rail to use flowify?? Please help !!!

STAIRS.skp (3.0 MB)

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img-041326×739 64.4 KB

Recreate the rectangle, weld edges

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img-04c1494×838 83.7 KB