I guess I'm responsible for the thread and need to chime in...after over a thousand reads by GNers.
First off...Race...HOW the ^&%$%^ do you know the weighted tension on your strings?
I am in total awe...as are the rest of the world!
But, okay, personal taste aside, there is a big correlation between mass and tone. Yer spot on about that, matey. For those of us that "live" playing directly through the board and out through great phones (as well as the monitors) there isn't a more discerning way to hear your own playing. (Like "duh"!) What is missed over monitors is very prominent in the phones...which means you'll start hearing where the mass does make a difference...(C-24 board, Beyer 770 phones, Dynaudio monitors, ProTools...including my left ear stirrup-bone having been replaced with a platimum/teflon one.)
So...yes...I do "mix and match" my gauges. (There's a 12 string set I usually butcher.) I also use a split pickup (EAD panned to the hard left and GBE all the way to the right) and the bottoms do need more mass as I can see it...so I will go heavier depending on if I want a chunky sound or not. The high three...where all the finger finesse comes from (for me) is easier to take care of because it's on it's own EQ'd (and effected) output. I most often compress the low three and slightly reverb the high three (using the ProTools 'brick wall' reverb setting).
As for changing them often...
If I am just noodling...no, it doesn't matter. But if I am recording something...and need to get back to it...it's nigh on imposkibubble to get the EQ right exactly as it was unless I simply put a new set on. As for breaking the high E...okay, they go but not as often as you'd think. On ultra lights you just GOTTA play lightly...OR WHAT'S THE POINT??? The axe I use is an old Ibanez Artist...1977. The icon on their pickups have a guy's hand with butterfly wings on it. (Ya gotta love the Japanese metaphors!) Seriously, everybody, it's the VERY "up close & personal" sound I get from playing lightly that I like. Certainly, it's frustrating to get used to them...because everything is in yer face...including lots of finger scraping/string tapping/string releasing/squeaks/pops & inadvertant chimes. You can (and WILL) come to incorporate these sounds in your style once all this slop is able to be played "in tune" where and when you want it. But, for me, this is the TOUCH I'm glad to cultivate...just like the way my wife likes it!