You and Nancy (President of Ditting USA) have very different views on what's required for complete break in.
Nancy famously says 300lbs. You say 15lbs. And -- since you raise the question -- I have no idea how to figure coffee vs rice break-in.
It makes more sense to me to just go ahead and break in the grinder, rather than trying to out-guess it; and to stop running rice, when running rice no longer, makes a positive, empirical difference. The last bag of rice I put my burrs' mileage at something like 120lbs rice and 40lbs coffee, and it made a small but still noticeable difference.
The difference was more visual (tighter particle size range at "press") than in the cup. In fact, if that last bag of rice made an in the cup difference, I couldn't taste it... but could with the previous bag.
Compared to other grinders I've used, Bunnzilla's taste signature for hot brewed coffees is decidedly "juicy," (in the sense of a very slight acidity which dances around the edge of the tongue) and it became increasingly distinct, though not stronger, as break in progressed. In my opinion, the "juiciness" is an inherent and desirable property which had been masked by lesser grinders; and a characteristic I'd noticed when using a Guatemala lab grinder for similar types of brewing and cupping.
BTW, when using raw rice as a medium, use a fairly coarse setting. IIRC, that suggestion came from Nancy as well.
More BTW, the "200lbs" was meant more as humor than prescription.
Drop a nickel in the pot Joe. Takin' it slow. Waiter, waiter, percolator