^+1. When you look at said charts most will indicate that 150/60-17 are "acceptable" so you won't be forcing the tire way out of shape. Which is nice because it gives you a lot of choices of 17" street rubber. I have a 150 on the rear of my X with no ill effects.
There is another issue to consider -- the bikes geometry. The 150 will drop the rear of the bike a little which can slow the steering some. Easy to fix and depending on your riding, this might not matter to you. For me, this was my reasoning to stay with the 110 on the front. The 120 is taller (in addition to being wider), thus raising the front. This choice limits your options.
One other issue -- don't mix n match your tires. The front and rear are designed to work together, specifically the way they roll into corners. If you want the most out of the handling of your bike, just don't.