Hey again,
Sounds like you've got a good plan there. A 'solution sequence' is very sensible, I can't tell you how many bits of paper I have laying about my desk with bullet points, or numbered solutions for a problem
I assume you have already achieved the interfacing with the LED display part? It suddenly hit me whilst I was reading that, most 'LCD volt meter' modules drive the LCD display direct, which is very different from LED displays. If it has teh ability to drive an LED display, or you've wangled a way to rig up the LED display then thats all good.
One little thing I just thought of..coudl you use a 'green' LED display? The human eye has its highest dynamic range around the 532nm part of the spectrum, giving you the greatest sensitivity between light and dark...a lot more so than red or blue (blue is crap for display reading)
I don't want to make your life more difficult by adding *more* options, but brainstorming is what I do. Assuming you are 'fairly' well versed in microcontrollers, which I can only assume you are since you mentioned a 2x8 LCD display which at the least would require basic initializing with a micro...
4a. Use a 132x32 graphic LCD display. The microcontorller would have to store bitmaps for characters, but could easily 'draw' the characters. Plus you'll have no gaps in them, as the display is graphic. I've recently become quite fond of these little graphic LCD's. More hassle than character LCD's, but not as memory hungry or scary as their bigger 320x240 cousins. You can create very neat custom symbols/characters, without the restriction of 'character spaces' plus fill the entire display making the digits/characters as large as possible. Hassle I know, but its doable.
Should you decide to go down the 'LCD module' route, and assuming this is a one-off..I can highly recommend ebay. Theres usually lots of cheap 'large character' displays, as well as countless mini graphic ones. I've recently picked up some serial 7-segment LCD's (12 digits) which are great for apps like this.
However you decide to go, some interesting reading:
**broken link removed**
**broken link removed**
(3M will happily sent you free samples).