Been using virosol for about 3 years now and always stuck to the 24 parts water : 1 part virosol.
Im generous on how much i use as i find the more you use the easier it is. I use anywhere between 5-8L of the mix on an average conny.
Get to the job, spray the first side with virosol mix, go get the rest of your kit & clean So long as not direct sunlight then leave on for 5-10 mins and it will work its magic.... direct sunlight just a couple of mins tops.
hope this helps
p.s. dont forget to take before & after pics