I wonder if copper coil would be bad for the compost...copper having a natural antimicrobial effect and all...
If you built it around a coil though, just pulling it out would do a lot to toss the pile. And using it as a feeder for rocket syphon would improve the efficiency on the syphon.
I was thinking about trying just a standard garden hose to mate up with the copper coil of the rocket stove. I'll draw something up soon and do a video about it.