You can't tell, unless you play with it. Straight grain is a good indication, tight grain is a good indication, but neither is a sure fire sign. The builder knows which shafts are good before he uses them, and hopefully doesn't use the bad ones. I throw away several beautiful shafts that have straight grain & tight grain & nice uniform color. I use several shafts that have slight grain wave or runoff, few grains per inch & has mineral or sugar deposits that leave brown spots or streaks. The majority of my shafts do have tight, straight grain & minimal or no color defects. The straight, tight grain is only the beginning stages of choosing a shaft. My shaft of choice for playability would be straight grain brown heartwood with hundreds of thousands of microscopic birdseyes that give that "fleck" look. It's ugly stuff but fantastic for performance. Of course everybody would be mad because their shaft isn't white, so I only get to use this kind of wood in my own cues or when a player actually knows his stuff & asks for old brown wood.