I presume before you simply threaded our "paperclip" through the slots for the regular clip, then added the dremel holes so you could run both simultaneously.
That's pretty much it. I found myself adding on the pocket clip fairly regularly. We had a roof leak recently and I needed to do some work in the attic. I'd come home, pull the light off my keys and add the clip. Then when I was done I'd take off the clip and put it back on my keys.
I found myself doing this quite frequently, and sometimes I'd need the light at work and pull it off my keys, then not be able to clip it to my shirt when I needed to use both hands.
The final motivation was thinking I had lost my light twice because it didn't stay attached to my keys. Once I found it in the pocket of my pants that I had been wearing previously. And the other time it was actually in my wife's car.
That's the reason I decided I had to have a regular key attachment and I came up with the paperclip idea. I did just what you suggested and put it in the existing cut outs. Once I knew that worked I saw there was no reason I couldn't have both.
Now when I need to take the light off my keys I can clip to my shirt until I'm done with it and it goes back on the keys, and I know it will stay there now.
This is my all time favorite key chain accessory. I used to have a big mag lite in my truck, but it got stolen. I don't even feel I need a light in my truck now. I'm hanging on tight to this little jewel.:thumbsup: