Do I need to loosen the nuts before adjusting the height and angle?
Not at all! You will need two hands to hold the base while you adjust the angle. No nut or bolts need to be shifted. Very easy.
What is the max height of the stand?
The most suitable height ablout 7.3 inches; If you have an oversize laptop please lower the height for more stability.
Will it be wobble when typing on the keyboard?
This laptop stand can keep stable (no wobble) if you type on the keyboard of lightweight laptop. But to keep a good posture, it may be better to have a wireless keyboard.