If you read my sticky, you know that I set up a race between the time it takes for the mycelium to consume all of the oxygen in half a quart jar and the time it takes for the mycelium to fully colonize all the kernels. The only way the colonization would work is if the grain were shaken, and shaken as often as one sees obvious growth, usually this is three times. That being the case, your jar will fuilly colonize in about a week, regardless of how much grain you have in the jar.
The hyphae need extra energy to jump from one kernel to the next. Shaking the jar causes the grains to bump into each other, if one grain has been at all colonized, some of the hyphae are picked up by the uncolonized kernel and it will grow much faster. If you shake, the most your hyphae will have to grow is less than an inch as you mechanicaly innoculate each kernel individually.
You also don't have to worry about "consolidation" as PF tec folks have to. They can't see inside their little pucks so they are never sure that the center is fully colonized. You know for certain that it is because you exposed each and every kernel to a bit of mycelium early on. The main reason you were confused is because you are still inheriting PF tec, it is a virus that was let lose upon the web and can't be gotten rid of. That tec inhibits people from understanding the mushroom and this is an example of that. You also don't have to pump your grow with 84 degree temps as grain and shaking will work about as well even down in the 70's. And, as you were hoping, shaking will bring all jars to within a day or two of completion so you can put them all in your chamber at the same time. But are you going to case that grain or what?