you don't want to shape the tip too much the first time that you hit the cueball with it because the more shape you put on it the sound of the hit will change when you hit the cue ball
Why?, that's the shape my tip takes no matter how I shape it. We're not talking dozens of hours here either, maybe an hour or less for the tip to change from dime to quarter. Makes no difference what brand tip I use, it's just the way I play that shapes the tip. I only use hard tips, so once they settle in, they stay that way for a year or more.
You can grind your tip to nothing over and over trying to maintain an unnatural shape for your game. Eventually you'll either buy tips by the boatload or learn to leave the damn things alone. Some people never figure it out.