As someone who only recently made the transition to a well-built custom UI with all the necessary raiding addons, I haven't really had the opportunity to configure much of anything within Grid except for its on-screen position and individual frame size.
I'm wondering if anyone could suggest some useful attributes to assign to my corner boxes (as a raid leader and main tank). I was thinking of doing something to this effect:
Top left - Aggro (red)
Top right - Incoming Heal (green)
Bottom left - Debuffed (color as appropriate)
Bottom right - ?
I'm planning on trying out the GridManaBars add-in, so that should solve the problem of needing to see mana deficiency. I also plan on stealing the idea of having both name and health deficiency displayed on every frame (provided it fits properly >.<).
(Edit - you can see the position of my Grid frames in this old screenshot: http://www.virtuousg...ages/vecui1.jpg)
I really think you're trying to do too much with your grid for your needs.
The incoming heal button only takes into account people using grid or sraidframes, which probably wont be every single healer in your raid, so as a non healer unless you're enforcing grid/sraid as a required mod, that indicator wont be much use.
Things that you'll actively use as a raidleader would be any encounter specific debuffs - things like insidious whisper on leo, static charge on vashj, even melted armor for al'ar would be handy to use as a maintank. You'll have to add these debuffs in manually, but you can go as simple as the rend on moroes, or amplify damage on prince, which depending on the intelligence of your raidgroup can be a very useful thing.
Colour coded debuffs on a corner icon sounds good in theory, but you really shouldnt be reminding people who can cure to cure.
I'd definitely reccomend you getting the manabar addon and missingbuffs (think it's called GridStatusMissingBuffs), and setting a centre icon to show when you're out of combat. I personally found that I missed out on seeing xraidstatus missing buffs because it was an addon that i'd scaled down and tucked out of the way, and no matter what peramaters I set for my multiple mana status bars, there was just never specific enough information when you really need it.