Yes. I ran .033 IFR's in the front for several weeks with .031's in the rear. It was just for testing purposes, so the next time I pulled the rear metering block I added the .033's to the rear just to keep them even so I did not forget what setup I had.
My theory was I only needed a small change, so I only did it on the primary side. I have been told to keep them the same front to back, but it did help me at the time. When I had the .033's in the front, I did only adjust the front metering screws to make up the difference in idle tuning. I did have to lean the fronts after adding the larger IFR's, which makes sense.
I would suggest buying enough to do both front and back, then add them to the front to see if it gets you where you need to be. If you still need more, then add them to the back and retest.

Note: I do like to see my metering screws set the same front to back (same side) and I can do so with the same IFR's front to back. Since I added my second O2 sensor, my side to side metering screw settings are a little different but they are the same setting per side.

"" it seems the secondary IFR really shouldn't be delivering incremental fuel in the 1K-2K RPM range but I could be wrong.""

I still struggle with,,, why are there IAB's on the "secondary" metering block?
They still affect the idle circuit, so I am guessing that the IFR's on the secondary side are still affecting the idle circuit the same way as the primary IFR's are too.