RectTransform - how to change height and width

I didn't use c# but this is what I did: I clicked onto the game tab and there should be a little section showing you the screen ratio. At the very bottom of the options, click the '+' option. There you should be able to make your own screen ratio. It may take a good while to get the ratio you want but it will change the width and height of the react transformer. Hope this helps @Kemorno :)