The 12th fret is the mid-point of the scale. It's usually easier to measure this distance than from the nut to the bridge, because an intonated bridge has slightly different lengths for each string.

The shorter scale length is easier to bend, but it gets a bit crowded in the higher register because the frets are very close together.

The longer scale length is easier to play up high, but it means making more of a stretch for chord work, and the string tension is noticeably higher.

I use massive D'Addario EJ21 string sets on my short-scale Yamaha SBG1000 guitars for really solid tone. I use D'Addario EXL110 string sets on my long-scale Wasburn A-20 and A-10 for easier playing up high.

Find what works for you. I consider anything less than .010" to be a spider web, not a proper guitar string. But then, I don't do a lot of shredding, so I need to make every note count. Don't worry about the string tension. Stevie Ray Vaughan used .012" strings on his Strats, and he pulled some amazing bends! Mind you, he built up his hand strength to the point that he was reputedly able to crush a tennis ball! :eek: