I have a few questions about my current grow...
Question #1 (easy one):
-What are some signs that i may need to add some Magnesium? Epson salt? and how much should i add?

the green veins in the plant will start to turn yellow and pale, sometimes the leaf tips will curl upwards. you shouldnt have problem with it with the 9-4-4 and micronutes. the sulfate of potash should help with mag too.

if you do decide to add something for mag watch out for the epsom salt...it can be easy to overdo it....you can also use dolomite lime or garden lime.