IMHO there are different things in motion when comparing different gauges "steps".
1) feeling: a lighter string can be better or worse depending on your habits and style.
2) string to string balance: I prefer lighter "lows" and heavier "highs" because I think that they match better in terms of sound
3) the sound on the string length/fretboard position.
4) percussive styles are the ones that are more influenced by the gauge.
let me explain:
1) we all pluck and pick different, with different angles and strength, depending on finger length ecc, so the different gauge can impact our way to pluck and pick. FE: I can't stand anymore the Thomastik set with that super light A string (70), or I usually prefer lighter strings on the low side, like the 55-70-90-105 set of Fender/GHS flats.
the position of the E string and the way I finger it (considering both hands) makes me prefer a lighter E.
2) I've noticed in most sets that a 80-100 matches better with 45-65 in terms of sound, for sustain, harmonics and clarity. however, it's a matter of nuances, and poorly noticeable in a band context.
3) IMHO lighter strings tend to sound better balanced all along the fretboard: a 105 E string, for example, gets a bit muddierd compared to a 100 when going up the fretboard, still maintaining a clear sound on the lower frets.
on the other side, lighter high strings tend to sound too twangy, so that a 45 G is better balanced than a 40. however a 50 G can be a bit too "hot" and "howly" on the upper frets.
4) as other users already mentioned, on the slap technique the gauge is more evident, as with a pick. usually you can hear a difference in the fundamental and the harmonics.
slapping a 100 is different than slapping a 105, so is popping a 40 or a 45. not to mention a 30-90 set
so, it's a matter of preferences, and the best set is the one that makes you comfortable. I always read about "balanced sets" and the math to create a set with specific gauges... I've always preferred sets that are unbalanced on chart, like the aforementioned 55-70-90-105 set of Fender/GHS flats, or the Rotosound RS66LD set.
they have tensions so unbalanced, on the chart, that they should be so uncomfortable
but I've always preferred those sets to the "balanced" ones.
ah, the bass also has some role!
FE: I'm used on some basses to the Rotosound BS66 set (43-65-80-110), and I love it. however, my Aria SB1000 didn't like it: the E string was too boomy, the G string sounded like a guitar, and the volume was so unbalanced that I had some difficulties playing it with the band.
I switched to the RS66LD set, with heavier G and lighter E, and now the bass sounds perfectly balanced: the G on that set is a 48, so like those sets with an extremely heavier G (also the RS77LS have a 50 G, not the labelled 45) that were typical in the 50's/60's.
most of my basses have this kind of gauge, even if it's not labelled, and I discovered it just by taste:
I've used for years the Rotosound RS66LD set, and until I measured with a caliber, I only noticed that the G was "tighter" than other brand's G, and here it is, a 48.
the Rotosound RS77LD set was an immediate love, and guess what? a 50 G on a "45-105" set.
I prefer the Fender and GHS gauge 55-70-90-105 to the La Bella 0760M I was used to (52-73-95-110), and also liked the GHS 45-95 set.
also the Brite Flat (GHS) standard set on my Stingray is wonderful, 49-62-84-108.
with more standard sets (Ernie Ball, D'Addario ecc) I prefer the 45-100 sets, and only use a 45-105 on my Mike Dirnt signature, that mostly play with a pick and need more "strength" on the lower strings.
you should try as many as you can and decide by your taste, not others.
