Best advice if your going to make a massive farm for kindling (I don’t farm combustion to annoying). Decide if your building this farm to produce shred for selling it, concrete, fuel or for personal use.
After you figure that out you can decide how often you actually need to harvest it. I do rows of 900 seeds, 3 wide 300 long. The entire farm currently is around 28k seeds if I remember correctly.
I only harvest when I need shred since I only use it for personal building blocks. Which makes it not a massive burden on me.
Hope this gives some insight from my perspective. Best of luck.