AV receiver maximum volume I can go

Hi folks,
another noob question from me:
I have these speakers:Q Acoustics 3010i which spec. says
Stereo Amplifier Power: 15 - 75w
AV Receiver (2 ch. driven): 50 - 125 W

Powered with this AVR: AVR-X1600H 7.2ch 4K Ultra HD AV Receiver with 3D Audio and HEOS Built-in® AV Receivers | Denon which spec says


I have set up speaker impedance on AVR to be 6 ohm (altough I could probably set up even 4 ohms but I read i dont need to do it in case I dont see any issues, some even reccomended to keep 8 ohms). Not sure If this seting influence AVR power output or If is driven by real speaker impedance (which is 4-6).

Nevertheless I dont fully understand those power outputs mentioning 1Khz and number of channels driven but I would expect I should be carefull with volume above 50%, but on 50% the sound volume is quite low. I currently have 5.1. connected.

My question is: Is there possible to say what volume on AV receiver I should not go above? 60%, 70%? 80%? Iam worried Icould damage speakers.
Thanks for your answers in advance!