After reading a lot about carbon buildup in Ford DI engines, I'm quite encouraged. I do plan to do some things to try to make carbon buildup less likely, most of which I would do anyway as a matter of good car care, or just enjoying it:
Use Top Tier premium gas (mostly 93 octane BP around here,) use good low NOACK full-synthetic oil (probably Mobil 1,convenient to buy and cheap in those 5-quart jugs, maybe Pennzoil Platinum or Castrol Magnatech,) warm the car up,avoiding short trips when possible and taking some longer drives periodically, redline it some (after break-in,) and keeping my software up-to date. At this point I'm leaning against getting an OCC.