It shouldnt be that hard to adjust your forks & fender to compensate for a 120/70. I would slap on some Pilot Powers (great tire). I have not tried them, but Dunlop's new "qualifier" was made to compete w/ the Pilot Power and is supposed to be a good tire.
Slap on a 70 - don't modify anything - the new tire will pick up little stones'n shit, that will smoothly grind their way through - creating a passage for stones to come. (Helluva scary noize though!) Just don't try your luck on newly tarred roads. :thumbup
After 50000 km, the scary noize will disappear..... (avoiding newly tared roads -100000km)
if you put a 70 profile tire you will and must modify the front fender i put a 70 on my bike and went for a 400 km trip at the end of that trip i had a fender that had no middle and alot of melted plastic allover:myfault , the tire grows on speed ( the middle gets higher than at stand still). and as too what tyres i ride on bridgestone bt012 they last nicely and grip well but if you want lots of grip michelin pilot sport or race absolutly fabulous tyres and metzeler rennsport had one on the front it felt like i had a steering damper very nice but the michelins and the metzler dont last to long.