I have studied string choice on each guitar I have. In the process for two of them as I don’t like change strings just for curiosity sake, so it takes a while to get around to trying the strings I want to try.
I have noticed each guitar has a string set I prefer to use. I’ll go over a few of them below. In general, I like playing 9-42 or 9-46. I have tried down to 7 and up to 12.
PRS Tremonti SE:
This is my first guitar, so I have the most data on this. I have tried 7-10 here and settled out on 9-42 or 9-46 Ernie Ball Cobalts. I like the sound of the Cobalts better than other strings of the same size on this particular guitar.
Ibanez 761SE:
I have tried 8-10 here. I prefer 9-42 or 9-46 DR Pure Blues on this. I like them best after they get a little used. I used the same set for the duration of BLIM last year and loved the sound after about 2-3 weeks of heavy use. I didn’t change then until I was struggling to keep them in tune. These strings have a round inner core on the wound strings. I think I like the sound of that and the feel.
Epiphone SG:
This guitar is temperamental about aggressive playing. A heavily hit E power chord will momentarily swing the E string out of tune and make the chord sour. I have repeatedly returned to 10-48 and I think the GHS Thick Core and the Dunlop Heavy Core do ok here. The bends don’t seem to be as easy, but I also don’t seem to play the songs that need it as much on this one.
Strandberg NX6:
I really liked the Dunlop Rev Willy’s 8-40 set on this. The tension profile due to the multi-scale fretting made string 1 have a little more tension than string 3. I changed back to a set of 9s after getting an archtop with 12s on it and having trouble changing between the two. The 8-40 are pretty light and you need to play delicately. I had trouble with the floating bridge here and eventually blocked it. The light strings require a lighter spring tension, and it was easy to bend things out of tune. Fingerstyle is not as comfortable as with 10s it came with. With 8s, the bends kind of just happen and you need to listen to not over-do it.
Self-made Strat:
Pretty new. probably be 9-46 round cores, but still some strings to try.
Godin Kingpin Archtop:
This one came with 12-52 and I was not able to make more than a semi-tone bend. They felt a bit heavy with finger style as well. The bridge on this is set up so I need to use a wound third string to maintain intonation. This makes the string choices very limited. I am currently on my first string change and have used D’Addario XL 10-46 with wound third string. I generally consider D’Addario strings to be dull sounding, but these were not over-priced like the very few other options. I can get my tone bends on this, but I do notice I work harder at it. It feels good with fingerstyle.
I think this is a personal choice. See what works best for you. I think playing comfort is the strongest influence, next to sound. I think trying brands is as good of an idea as sizes. It is best to make a recording so you have a reference to go back to.