Are EMG's height adjustable or are they fixed like some pickups on schecter guitars?
they're adjustable. also you dont have to worry about height so you can put them right up under the strings
They're as adjustable in any given situation as any pickup of the same form factor.

They need to be adjusted quite close to the strings to get a decent signal, because they don't actually have super-strong magnets. Also, it means that you don't get string pull.

I have mine 1-2mm from the strings when they're fretted at the highest fret.
^ Word.

People always comment on how close mine are
我会关闭我的耳朵,和我的心; 我会变成一个石头
"I will close my ears and my heart and I will be a stone"