I just got the 1200, it looks big in photos, but trust me, when you get it, you'll be SHOCKED by the size and weight
I was Jesus this thing now weighs like 50 pounds
Yeah if you're gonna keep it in one spot go for 1200, but if you want SOME mobility and little less weigh go for 900.
Yeah make sure about the wires. Mine reached but the 8-pin and 24-pin cables aren't run through the back, their up front and kinda ugly
Go for 1200 if I was you