Danny, had a chance now to read through that post properly! I think it's actually very similar to the concept I have, though you have a little bit more panning detail added, and I have included frequency detail also.
Basically the way my image works is as follows. Link to that image again:
http://www.mattlyonsmusic.com/images/Layout.jpg The vertical is all about where that instrument 'sits' in the frequency spectrum. I have not put any specific numbers in as I'd rather work off my ears but numbers could be useful, don't know. For now, I have not included them. The left and right is obviously the panning. I didn't really show it in that image because it was so quick, but essentially the bass and kick would normally be a narrow circle, indicating a very tight stereo image. The verse vocal would also be very tight. In the chorus, I'd be adding more of a stereo verb/delay/chorus/doubling or whatever to make it a bit wider. This would normally be visible in the image (it's not really clear in my images posted). We all know an instrument can be high or low (frequency), left or right (panning) and out front and at the back (reverb amount). I basically included everything here but the depth of the part. I don't see that as so important and if I can get everything sitting right at the face value, I can than push certain things back into the mix if I want to.
So basically the position and size of every circle in my drawing is a direct representation of where I percieve to hear it. I can visually see if there will be any clashes. I draw the image from a combination of listening to how it is at the moment, and where I ultimatelly want everything to sit. Then I can use it as basically a recording/mixing chart to work off. Allows me to quickly look at where a part needs to sit. I didn't include all the drums in here but I can add them too. I can see where gaps are and work out how to best fill them. I can easily see if things are getting too cluttered. I can see instrument dynamics between verse and chorus to ensure my chorus kicks in well.
The triangle/tapered shape I had in my drawing was based on the fact that you don't pan bass instruments, typically. Bass is non directional, so you get more bang for your buck going equally from both speakers (I know you are aware of this, Danny, just giving a full explanation to everyone!). It's probably a little weird looking, so I might actually leave that out next time and just make a big box.
If I draw each on up on a big bit of paper I'd have plenty of room to start adding detailed notes such as type of sound, reverb amount and panning/frequency positions if it helps.
So that's my one and I guess I have taken a few components from yours and would combine with mine for a little extra detail!
An interesting technique I made that bold to get people to read who may not be reading the whole post ;) Also. I remember you mentioned a well eq'ed instrument you should be able to crank in volume without really losing any other instruments due to masking (within reason of course). I took this concept and expanded on it. What if you crank an instrument you are working on 6dB (or even more) and then eq it so you can hear the other instruments clearly. Little bit of back and forth and then bring everything back and re-adjust your levels with a perfectly eq'ed track where everything MUST have its own space! Dim Solo at -6dB could make this a real easy technique when having trouble eqing a part into position. I tried this out the other night and it really helped get things sitting a lot better in the mix. I highly suggest people check it out.
Lastly. Off topic. Went into an audio store yesterday. They had a pair of $20,000
Adam S4X-H monitors. It was a VERY temporary demo in the shop. I went in today to listen to them with some of my own music and they were already gone! So shattered. But wholly f'ing wowza!!! These sounded AMAZING!!! They are midfield monitors so plenty of punch as you'd expect but I was just absolutely blown away. That midrange was unbelievable. The POWER these things put out was immense. I never expected to hear something like these unless I went to a pro studio. But damn I REALLY want some :| To anyone who hasn't heard monitors like these, make sure you hear them if you get ANY opportunity. They will just blow you away and make your day... Now I want to hear the S6X's :)