[Arran]

You will have to experiment with the brushing lacquer to see if it has to be thinned or not, maybe on a scrap of plywood. I haven't used the Deft brand of brushing lacquer but have used the Watco brand with a brush, it's about the consistency of Aunt Jemima pancake syrup. Some say that you can spray Watco without thinning but I have no idea about Deft, I think that the main difference between brushing and spraying lacquer is that brushing lacquer has some additives to make it dry slower.
Regards
Arran