You dont want masterwork hits on your GA vulnerable, you want it on the temper or normal rolls. The masterwork upgrade only effects the standard max roll, doesnt include the extra 50% for the GA
Never undersell yourself. This is a fantastic build. And I love your humility. You say that you just new -kind -of . Well, you certainly know what you are talking about. I've played rogue a few times. But your build is rock solid, and I love and appreciate it . This build of your s can only get better . I'm 54 years of age and have been gaming since I was 8 years old. So you have done very well .Good job
I have near exact same setup but I added andariels visage for a little more boss dps. Killed lilith after a couple of tries and all my gear is under 7/12
The other two are just worse. You neither use Combo Points nor do you spend Energy. So Inner Sight is the only spec to give you any benefit in this build.