I found this useful pdf showing all the different Ateco tips. However I noticed that they appear to have two separate series of plain round/open star/closed star tips: tips #1-12 are plain round tips, but so are #800-809. From what I've found, it appears the lower series have smaller tips while the higher series have larger tips, but there's still some overlap. For example, Ateco #7 has an opening of 0.15", while Ateco #800 has an opening of 5/32"=0.156". Does anyone know what's the difference between the lower/higher series, especially when the sizes overlap?