I do not think the topic of tuning harmonicas has to be mysterious or worrisome. Here is my idea. Other people may have other ideas.
First decide if you want A=449, A=440, A= 441, A=442, A=443, etc. , based on the tuning of the people, piano or other instruments you want to play with.
Then ask yourself if you normally play notes without bending them, or if you bend your notes most of the time. Decide what your style is.
Next put your assembled harmonica into your mouth and a tuning meter in front of you. Set the tuning meter for the A that you want (438, 439, 440, 441, 442, 443, etc.).
I think that is a very simple system. It is easy to understand. You can add some fine points, but that is the basic system.
Then you have to spend the time to tune your harmonica