DJM800 Ideal Gain Stages

I have a pretty straight forward question.  I'm just curious as to the ideal gain setup for the DJM800.  I know all about gain stages but I'm talking the finer points of these units.

What is the ideal level for the "Channel Level Indicator"?  +7?  +10?  Is it more ideal for the the Master be at +7, +10?  I see people DJing with meters at full blast all the time & that doesn't seem right to me but +7 seems a bit too low.  Maybe I have answered my own question but I would love to have a little information from the great folks at pioneer regarding this topic.

The reason I ask is because I am using the DJM800 with line level signal at 24 bit 48kHz wavs with a Funktion1 sound system for the 1st time in a few week.  I know these finer points may not matter as much on a smaller sound system but on a big Funktion1 I think it will make a major difference.

Thanks Pioneer Guys!

Love your products!