Ok, you haven't mentioned your current weight, but congrats on coming down from 310. I'm sure your body thanks you for the improvements you are making. I'm going to come up with an arbitrary weight, lets say you are 265 lbs now. If you are eating 1.5g of protein per lb of body weight, thats 1590 cals from protein alone. That means that you are only getting 710 cals from carbs and fats combined. 50 grams of fat isn't a lot, so lets arbitrarly say you are eating 50g fat. Thats 450 cals. That would leave you with only 65g of carbs a day. In order to grow, you'll probably need to up the cals from carbs or change your ratio. So keep this in mind for your overall approach. I can't say how many carbs you need without seeing your diet, your pics and seeing how you respond to food. What you'll need to do is increase the carbs and see how many you can handle without putting on too much fat. Remember that growing muscle and losing fat are kind of two different goals. You can do both at once if you have the diet nailed, especially when you have a decent amount of fat to lose. So watch yourself closely. Measure out everything and make adjustments as needed. 

As for arms. The more work you do for chest and back, the more your arms will grow. Still some people have better gentics for arms than others and you may find that you need more or less volume for arms than for other body parts. I have seen people do well with higher reps for arms. I usually work in the 10-25 rep range for tri's and the 10-16 rep range for bi's. I find that when guys go very heavy for arms, they tend to get more injuries. If you are killing it on chest and back, your arms are already getting a lot of stimulation. 

And my final thought...Bodybuilding is an illusion. The smaller your waist gets, the bigger your arm looks. If you hit a side chest pose and your arm is 15 inches, it's going to look a lot bigger with a tiny tappered waist than if you have a 38 in belly. Work on the illusion. As you get leaner, the arms will look bigger than they are