You will need some spacers under the mounting screws to raise the adaptor above headphone body, so that the puck has room to slide on. I used ~2mm thick nylon washers that I had, but any non-conductive material will work.
I used a cheap set of ANC headphones in hopes of taking advantage of noise cancelling, but NC is only designed to work through BT. Plugging into the jack disables it.
If you do use rechargeable ANC headphones, they have a Li-Po battery just under the earpiece body on the same side as the jack (at least mine did), so be careful if you plan to drill your mounting holes without first disassembling the headset.
I really enjoy the ones I made. They are very comfortable and lightweight. I hated the Howard Leigh headphones I had before I made these. Felt like my head was in a vice.
Oh, another thought for anybody planning to do the same. Make sure you get a design that gives room for the band swivel to move and a nice surface to mount the puck.
As you can see in the first photo, the swivel hits the puck on mine but was enough room to flex when I put them on.
There are so many styles of inexpensive ANC headsets out there (some don't have the 3.5mm jack). They are discounted right now for BF at around $30.