I'm still not sure what the best placement is for everything. I decided initially to put the power supply at the top of the iMac above the stand attachment but realized that display wouldn't sit flat.

I determined that the power supply fits best below the stand attachment where the hole for the power cable used to be. As it would seem the power supply mostly fits and thats what I will be doing for this. From what I could tell at this point in the project, the case will not fully close but it seems to be the best I can do.

After test fitting, I decided to mount the power cable plug to the left of it and cut a hole using the dremmel plastic cutting discs and the engraving bit for finishing up along with using the metal polishing wheel to smooth the edges out. I then drilled holes and screwed it in with some random screws I had lying around. Initially I decided to screw from the inside but later on I moved the screws to the outside as they seemed to stay better. I then used kapton tape to secure the power supply to the right of where the power cable was. If I were to open it again I probably would use some adhesives glue as well.