how much paint to do all fairings

[ross46]

hi, hopefully a nice simple question, i want to spray my bike fairings kawasaki green and then do a design with black and grey, but to paint all of my fairings how mucg paint am i going to need? 1/2 a litre? a whole litre? i am using a compressor and genuine kawasaki green from a paint shop, any body know how much to order as it will be thinned down? also any tips welcome, thanks, Ross