A couple different ways depending on the drum I'm using and what control strip I happen to have. C-41 control strips come in several different formats. 35mm full frame and a smaller (narrower) format that I can't recall the name of. My current batch is the 35mm full frame strips. These can be put on a Jobo reel and run in a 1500 series tank. Assuming the process conditions are the same as your sheet film this works pretty well. I'll do this first to see where the process is and make sure the chemistry is still in good shape before running a bunch of film.
Originally Posted by anikin
The most reliable way is to run it in the same drum as the sheet film so that it sees the same process conditions as the sheet film. This way it sees the same agitation, temps, and developer exhaustion rates as the sheet film does. With the 3025 expert drum for 8x10's, I slide the strip in between two of the sheet film guides. I'll do this from time to time to make sure density and contrast conditions aren't drifting on me.
If you're using 3010 or 3005 expert drums it's a little harder but not much. I put little tabs of black plastic electricians tape on each end of the control strip. Insert this in one of the tubes on the expert drum and stick the ends down. The ends of the strip where the tape is don't get developed but the area where the control patches do. It works fine. If you're using 2800 series drums you can use this same method.
The 35mm full frame strips are a bit long for the 3010 4x5 drum so in this case just running it on a reel with the 1500 tank will get you going.