I want to make the vanilla malted cookie recipe from the Martha Stewart Cookies book. The recipe says to use a 1/2" star decorating tip (Ateco #825). What number would that be for Wilton tip?
1/2" inch star? Wow, that's big! I would think either 1M or the 4B. the 1M is a big tip. Does your book show a picture of the cookies?
Maybe a cookie decorator here will pop in and can give you a better, more qualified answer.
I have a 4B that measures just slightly less than 1/2 inch.