I have some spacer made but I removed them.
I am 1,8m (I think 6feet) tall
I started with 20mm and after I while I remove step by step 5mm until I got back to the standard. The high handle bar is nice for riding on simple tracks but when you start riding extrem the lower bar is better for lifting the front wheel. Also when riding fast on a motocross track the lower position of the bar has advantages. More feeling and pressure on the front wheel e. g. more control on the front wheel. A lower handle bar is not that comfortable but much safer to ride extrem or fast.