okay I went old school and just modeled the geo. I used quad draw and started with the holes (not shown - I forgot to grab a screen shot). Go here for screen shots ...

https://imgur.com/a/67OiN

The I filled the gaps between the holes, offset the hole polys, added a couple edge loops to hold the corners and delete the hole polygons. I only built half as the model is mostly symmetric (Image 1).

Then I mirrored the to get the top shap (Image 2).

Then I added a non-linear bend deformer and scaled to correct for the loss in width from the bend. (Image 3) (I also extruded the inside of the holes to give a little thickness.

Then I extruded the outer edges to get the top thickness (Image 4).

Then I added a couple edges to tighten some to the corners (Images 5 and 6).

From here it is just a simple process of extruding to build the remainder of the model.

Hope this helps.

Rick M.