When it comes to bread recipes I wouldn't worry too much about being precise at first, you kind of figure out what works best for you, with your tools and your oven, so take them as a general guidance.
If you like sourdough/rye bread, give them a try once you're comfortable. Getting your own starter started can take a bit of time (lost of good info out there about it), but once you get your first decent looking loaf done you'll feel like the king and queen of the world (I know I did).
That being said, you can go really nuts with the details with this, if you ever want to achieve your perfect loaf whatever it may be.