Rev9 Update:
I changed the coding of how the inside cuts were done & made them more parametric. You can now change the variable InsertTool_Gap to the gap distance that best works on your printer. The default is .4 which was the original. .5 worked better for me. I added a PDF file that shows some of the dimensions that might not be obvious what they are. I also added 2 test stl files & the openscad file I changed for the test prints. I only created test prints for the US version. I took the chamfered vertical cuts out as the default as it seemed like extra plastic hitting the EMT would be better & you do not see those sharp corners once it is attached.

After creating the 1st parametric remix of this design, I decided to upgrade it a little with a few changes. The amount of plastic the EMT Bolt Head rests against seemed very short & the angle of those connections was not parallel with the inside cuts. I increased the plastic support for the Bolt Head to 6mm from the 1.75mm(IE) to 2.14mm(US). The EMT screw mounts are also now parallel with the side Tool Holder slots & Radial to the Vertical EMTs.

There is one openscad file that you can create either the EMT mounting bracket or the tool holder that connects to that mount. There are 44 variables you can change. That is a lot, but you probably only need to change several to meet your needs. They should be well commented & I included a PDF file of the 2d layout I used to compute the 3d geometry. I hardcoded some of the dimensions into the code rather than use variables & the PDF file could be useful to see what those are.

I have not printed this, but have checked the design as best I could. Feel free to point out any problems you may find in this design or if there are variables you do not understand. I included 3 sample stl files, A US EMT Mount, an IE EMT Mount & a 49mm Tool Mount.

For the Test Prints, I changed the following variables