This one had about 2500 units. I don't keep an exact count, but I usually know how many total units I've folded and can eyeball how many of those I have used.
I draw out a very basic outline of what I want in terms of shape, but it's really not too detailed. It's a lot of trial and error, but I've done a lot of modular work so I usually have a good grasp of how it needs to go.
Western Dragons are usually green or blue Well not a solid colour but maybe make it mostly green with some darker green? You could always paint your final model too, I've seen people do it and it looks really good.