I can't remember the brand names offhand as it has been a while since I used the stuff, but if you want a good finish use the 'thick' plaster to get a good base as it gives plenty of working time and you can correct surface irregularities. You can scrape off a lot of bumps that you didn't notice when you put it on while it is still soft. While it is still damp you can skim it with your 'fag paper' plaster. The reason for putting it on a damp surface is that the water will not be drawn out of the skim too quickly thus making it difficult to work. When mixing the plaster add the powder to the water, when you are close to the correct consistancy leave it for 5 mins as it will stiffen a bit more, you can then adjust it with a little more water or powder. You want the consistency of soft margarine, if you make it too thin you will get cracks when it dries.