Serum - 10iu intra muscle 3ish hours before blood draw, preferably in a smaller muscle like biceps or triceps. Fasted is best.
18+ is a typical good score. Anything over 30....might be something else.
Igf - you need igf tested before you get igf levels using gh. Gh doesn't reduce your natural igf levels so, you need to know what they were before hand.
So if you go in before you start gh and you score 150,that's your baseline. The gh will elevate you above that number and that's how you'll tell if it's good or not.
4 weeks at a constant dose is plenty of time to get elevated igf. Timing during the day doesn't matter but, fasted am is really best for any type of testing.
80-100 points per unit daily is average. So if you use 3iu Ed, you'll want to see a 240-300 point increase.