Use whatever you are comefortable with.Also something you could do ,when you make your stitch and flip method,after you have sewn diagonaly across the background square[befor you trim the excess]sew them again 3/8-1/2 in from the first line[towards the scrap square]then when you trim the scrap square you will already have another 1/2 square triangle sewn for another project.Instead of an odd size triangle that doesn't seem to get used anytime soon.