At one point in history, it was a secret you were only told under strict instructions to keep keeping it a secret
that Jerry Bird used all o.o18 gauge strings for his top E, C, A on his Rickenbachers. GIBSON-brand plain strings it was to be (yet another closely kept secret!) because the other brands just didn't have "that" sound (in those times, maybe there was some truth to that, I don't know).
I had that setup on my Rickenbachers and even at 22" scale it makes for a "rebar"-kind'a top E, it's OK on the C and wobbly on the A. BUT, it DOES help to get yet another baby-step closer to his tone.
One thinks of strings in "diameters"... actually, what shapes their timbre and how much they excite the pickup's magnetic field has more to do with their CROSS-section... it's all about MASS of the plain string or the wound strings CORE(!). And even a small change in diameter makes a considerable changes in cross section and thus mass.
OK... I try hard not to be binge writing away.... but:
On my Rickenbachers I nuanced it out a bit, by going 20, 18, 17 to keep tensions a bit more manageable.
On a PSG tension and reactions to tension changes (changer) is yet a bigger issue. So is intonation because on a PSG one would typically have more strings which need to stay "in tune" among each others.
And scale lengths are usually bigger too, and on most guitars the key head and thus total string lengths of some strings (the ones in the middle) even longer than on a 1930's Ricky.
But still with the same thought in mind, I keep my top E at o.o15 strung fairly stiff, C at o.o18 and D at o.o17 and on some guitars even o.o18. My A is a o.o22W because I like the intonation stability because of the higher tension.
I had the same o.o22w on my E9ths on the middle G#.
My beef is with the bottom strings on C6th. I used to have a low D instead of most people's C. Now, on my 12 string C6th I have added a low C on the bottom too... so I have F, D and C.
I always had a fit with the wobbly feel of a o.o68 on the bottom C. Some have o.o70 there and I am inclined to that too.
On a keyed guitar, having the D on the second last tuner makes that string about an inch longer than it would on the last. That helps too.
On guitars I can fit it, I now use o.o74 on the bottom C and I thoroughly enjoy the solid feel and more "lively" sound of it even above the 12th fret (although I am all diagonal playing... there is no real need to play the bottom C over the 10th fret as that note in conjunction with chords can be build off clearer ringing strings in the lower frets.
Most stringed instruments with more than 6 strings have different scale lengths, like the Piano or Harps... which follows the rules handed to us by physics much better. Even on a Vibraphone the tiles don't just get fatter, but longer too, so the timbre remains more homogenous in all tonalities.
so, 'nough 'bout that!... J-D.