I guess if that is what works for you, the main thing is to compare diff settings to something that you know works for a given load/terrain, or doesnt , and then you adjust for that.
I learned about gear inches about 25 years ago, so that is what I know and is a good reference to gearing changes that I have done in the past and relate X number of g.i. to various terrains that I have toured on.
also, i have never had a cadence bike computer, so am not really familiar with what X cadence feels like in terms of numbers, as I dont really know what my natural cadence is or in diff situations. I have however spent lots of time climbing at 6-9kph but have no clue of what cadence I was pushing.
I never have had a cadence sensor either, but I can calculate it easily enough if I know the gearing and the speed. 90RPM is my minimum default cadence, unless I stand or soft pedal, when I'm fresh I spin between 100-110, with a few spurts up to 120.
I had the displeasure of using a 50GI (21.5km/hr@90RPM) low gear a week ago, My knees hated that, every stoplight was a slow crawl getting up to speed. Never again.