@Nigel Ford
Don't bother with spray malt, it doesn't dissolve very well cold and any change in flavour to your beer will be virtually unnoticeable. Use ordinary table sugar, its cheap, easy to handle and predictable. About half teaspoon per 500ml bottle should suit the style. Or if you want something a bit more detailed use this
https://www.brewersfriend.com/beer-priming-calculator/
And between now and Sunday if your beer has definitely finished put it in a cold place if you have one to help drop the yeast so you are bottling clearer beer.