I know thread is a little old but thought I might give you or others thinking about occ med and pmr some insight. If you go the occ med route you can save some time with residency but will be stuck with occ med so you if change ideas or career plans you may be stuck. However I started moonlighting at an occ med clinic 4th year of pmr residency. After graduating I ended up staying there and currently am the medical director of the clinic. Instead of referring many of my patient for simple injections and for further work up of some injuries to physiatry, I just take care of it myself and sometimes the other docs and mid levels here will just have patients follow up with me because its easier then getting the approval from insurance companies some time. I havent made my decision yet, but they regional medical director has offerred to get an EMG machine for clinic so I can stop referring those out. I may also change mind and go back into a PMR position some other time. Occ med hours are pretty good and I can moonlight covering weekend calls and such at inpatient facility to keep those skills up and have done just that.
My suggestion if you are thinking about both things is go PMR as it will open up more things post residency. After residency you may not even want to do occ med, physiatry gives many career paths.