Here are a couple ideas to consider: I would say that most of the logs shown in this post could have done fine with only half the number of plugs used. Consider that the mycelium runs along the grain much more easily and quickly than across the grain, so a line of plugs inserted in a spiral formation along the log will be much more efficient (in several ways) than a row that goes straight down the grain. I look at this from a frugality standpoint, in that I can inoculate twice as many logs using this spiral, spread-out pattern; but also I'm wanting to get the mycelium to spread out quickly to block competitors...and fruit quickly. Ignoring frugality and just wanting the mycelium to spread out quickly, the spiral pattern is still very efficient. I also put a few plugs in the ends of the logs, in between row-ends, for the same reasons.
If Western Oregon were its own state, fungus would be the state flower, so maybe it isn't so critical in drier areas.
Drawing of plug pattern, and photo from a recent hike (not a 'selfie'):