Way too Many Instr/Vox to mix..Suggestions

[psycho_monkey]

That doesn't sound THAT impossible...you're right, you're never going to hear everything at all times, but treat eg all the keys as one big multi-textural pad, and you should be able to leave them all in...you just won't hear the detail.

have him bring in a reference track...point out the the big reverbs on the drums etc disappear when the track is at it's fullest (ie you hear the reverb when there's space in the track, and it's an illusion when the track is full), and emulate the same for your mix.

Shelving/filters are definitely helpful, as is splitting things for different parts of the song (eg full range acoustic for sparse intro, hyper filtered acoustic for biggest part of song where you just want to hear the attack). On things like Def Leppard, this would have been done by multing a signal onto 2 channels of the desk, and using mute automation to cut between them...a DAW makes it easier!

It might not be easy, but it should be possible! But contrast is necessary - if the song is one wall from start to finish, it'll be fatiguing - again, reference the tracks he likes, and point out the arrangements. Just the odd moment of space can help - eg muting everything on the big drum fill so you hear the drum reverbs (classic 80s trick) and then you don't need to hear the verbs in the full sections so much.

It's a lot easier to write about this stuff than to actually do it of course...good luck!

[suedesound]

filters and eq are your friend. don't be afraid to make something sound horrible when soloed, if it fits in with the track it doesn't matter. i had an album similar to your issue and muting things when they aren't looking actually works. you don't need the stereo room mics on acoustic guitar all the time.

[cpstudios]

Thanks Guys. Definitely some good points!