I’m also a firm believer in changing a single element at a time to the extent possible - the essence of “dialing in.” Combined with a multitude of information gathering, it’s hard to go wrong.
I’ve never brewed a kit, every recipe started as a blank sheet, only because it forced me to understand what the ingredients [and other factors] were doing for me in the brew process. This approach has served well, although, as mentioned requires patience AND good record keeping!
-Cheers!