Sizing

Got my BFG out yesterday for a re-string.

While at it, I took the opportunity to try what Rick Beato proposed - that thinner strings actually give a more favourable tone. The theory was that thinner strings actually got less in the way of magnetic string pull & overall instrument resonance. He & a few musicians even tried a set of 8s in a Les Paul which is courting trouble in terms of string tension but that's how Page (Les Paul) & Malmsteen (Strat) got away with cheap tricks while making tone count.

I have no 8s with me in the mean time but my BFG got a set of 9s for this experiment. Verdict:

Clean

Cleans & anything near clean in the amplified world, benefits from a thicker set of strings. I'm coming from the perspective of someone who seldom dwell in the clean zone but at this point in time, actually heard the difference. This is why we prefer 11s & 12s in our acoustics, yes? 

Driven

This is purely my take, folks. Thinner strings give your driven/ distorted tones a breather. This is especially true for the wound strings as more definition comes to play but for many of us, the lack of appropriate string tension with regards to the guitar's scale length bothers us more than the tonal benefits. Also, whatever benefits of having those in our instruments would perish if we observe a very aggressive string picking style. However, telling players in the rock, metal & other intense music domain to cease picking like a beast is futility.