I have an iPad 2 with iOS 7.1.2. My canvas size was usually the default given to me when I create a new file and layer sizes varied depending on the project that I was working on.

My first project was making a background for a piece of clip art I made before (I did not have to worry about crashes as frequently I do now and rebooting my iPad fixed it at that time). I used the spray paint and dot tools for my background, and when I went to change some settings for the spray paint, the app crashed. I tried and failed to finish this picture about 3 times.

The other project was a simple lineart drawing. The canvas was the same size, and the actual drawing was pretty small. I only had about 2-3 layers so that I could color it in. When I went into the layer menu, the app crashed and my file corrupted.