catdog,
I'm sure there's a ton of info at this very site. myself, I just got some rear-window defroster repair paint ($7 at AutoZone) and put down one big blob - covering all 4 of the bridges. next, I took the edge of a very fine flathead screwdriver and scratched 3 lines - isolating each of the 4 bridges. now my one big blob is 4 small blobs. looks something like this :|:|:|: do you follow? you will want to do all this under a good magnifying glass, and don't fire it up until you are certain that the 4 blobs are completely 100% separated. if current flows from one bridge to the next you will most likely regret it. go for it - as long as you are careful you'll have nothing to fear.
mike