Here's your 101 guide to baking/cooking conversions for my recipes that I publish. The reason I bake using the North American cup measurement is because I was never brought up with weighing scales in the kitchen. My Mom always used cups, as a result, it is what I am most comfortable with and used to when I work in the kitchen. The cups measurement uses the volume of ingredients as opposed to their weight. I also find that using cups is a quicker and easier way of measuring out my ingredients for baking. If you are looking to find measuring cups for your baking, I know they can be found in Avoca shops and most kitchen supply stores around the country. Also, a cook's measure can be useful for converting other recipes from or to the cups system.
Here's a link to an incredible site that has conversions from cups to weights for almost every ingredient you can think of, in alphabetical order! Really useful -
Quick tip: If you're stuck, 1cup = 250ml on any measuring jug you are likely to have in your kitchen.