Knowing what's going to happen to your film when you push the button is nice. Some may even say it is important. For me, it's like knowing what the piano is going to do when I press the key. For nearly everybody, I'd say get that far: know what's going to happen when you push the button.
Beyond that, it's up to an individual's temperament. Some folks look outside and see a mass of details, and measure everything in sight before deciding if it's a nice day. Fine. For them, I heartily suggest Beyond the Zone System.
For me, well, if it looks good, and I feel good, it's good. I have a less numerical approach, and it suits me well.
If you are more confident in an analytical, numerical, approach to life you'll be confident and effective only if you bring this approach to your photography. If you are more intuitive, don't on any account start drawing graphs.
An incredibly effective and reliable approach for the intuitive is to begin with a manufacturer's suggested Exposure Index and development time. Pick a scene that is the kind of scene you like to shoot and make a series of exposures at different settings, and give them the suggested development time. Make a series of proof prints. You'll probably have a couple pictures that are close to what you like: pick the one you like best, and note the exposure index you used for it. Load a second roll, of a few more sheets, and makes a series of images that are at the same setting, and give them development times. I'd choose the manufacturer's time, 20% more time, and 20% less time. Make quick prints and see which one brings you closer to your ideal. If you like the results, shoot that way. If you think an in-between setting is better, go with that.
This is no more than applying sorting theory, and is equally effective to less integrative approach like BTZS. Use what makes sense, keep notes whatever you do, and go take pictures.
Most importantly, SHOW us the pictures !
good luck