See your lug. There will be written some thing on it.
Either 1.5 or 1.2
1.5 means 1.5 turns per mm
1.2 means 1.2 turn per mm
With stock rims there are about 9 to 10 turns to tighten the wheel.
If you put 8 mm spacer you will be compromising on 8/1.2 = 6.6 turns out of 10 so you will be left with only three to four turns.
You can further calculate for your scenario
Feel free to ask if you have any further query
Sent from my SM-N920C using Tapatalk