I think I can write a book on the subject. I always was taught to select bamboo on length between nodes, sand and straighten, heat to temper, and then weigh the shafts. At that point separate them, then weigh my nocks and points. At that point I can check my list of what point will weigh right with what shaft and nock and assemble an arrow that will weigh very close to the next. Fletching is long and low and its weight is negligible, and if an arrow needs an adjustment to make weight I can use a horn washer or something to get it to scrape by, or scrape/sand to get it down. I personally make my heavy war arrows to within ten grains top to bottom. If it weighs the same, it'll shoot the same. There is no spine measurement. I was handed a bucket of different arrows and told to practice until there was no difference. It took time, but it's completely possible. I have my preferences (I shoot 7595s from a roughly 50 pound bow and can hit bumblebees) but a shot or two with a bundle and I would be OK in the woods with them. I don't believe in spine-I was taught that it's a crutch and a fallacy. I know that deflection is a real thing, but I never let it pick my shafts for me. I can always adjust my grip or where I'm aiming, or even my draw length to compensate.
I still shoot with the same techniques used nearly two millennia ago, and if I get dropped in the woods, I can still take sticks and rocks and make my own bow, string and arrows. When you learn that, differences in arrows kinda go away.
Or, throw enough shaft weight at it and call it a day.