Forget the internet. As previously said, get a good manual, trim your cases to the same length and use the recommended starting load.

The key to making good ammo is consistency. You probably don't need to weigh each case and measure the volume. You probably don't even need to sort by head stamp. You probably don't need to measure and weigh each projectile. But you could do all that, if you wanted the most accurate ammo possible.

But checking case length is a basic step you should do.

You already know you need consistent case length to get a consistent crimp. It becomes critical as you approach maximum loads.

Check your case length on subsequent reloadings. You will find straight walled cases tend not to grow too much and don't need trimming very often. At some point you'll decide, based on your own experience, how often you need to check case lengths.