Okay. First, congrats on the new snake. My boyfriend bought me my first one, and it's an awesome feeling.
To take up some space and make her feel more secure, you should get two, smaller, identical hides and put one on the hot side and one on the cool side.
As for food, get a small scale and see how much he weighs and take the scale with you (if possible) and try to get a mouse that is 10-15% of Iggy's body weight, or judge the size mouse by the largest girth of your snake.
As for the lamp, do you have an under tank heater (UTH) as well? or just the lamp? If you don't have a UTH, you should invest in one. Ball pythons use belly heat to digest. With a UTH, however, you also need to get a thermostat to control the temperature so Iggy doesn't get burned. Your lamp is going to KILL your humidity as well.
You could probably find a cheap hygrometer and if it turns out your humidity is too low, get a bigger (not deeper, but wider?) water dish (this might be wise anyways because your tank is so large for such a tiny snake). You could also place a wet towel ontop of the tank, or create a foil top (there's a sticky for them somewhere on here) by putting a few layers of foil on the screen top, taping it down, cutting a hole for ventilation and one for your lamp if you keep it.
Hope this is usefull and good luck with Iggy!