A few days ago tuff posted a question dealing with spraying poly. Although this article, doesn't deal with the specific question of nozzle size, it does contain some useful info on finishing. The website also contains articles and plans for some other things that frequently appear in this forum, such as a plan for cross-cut sled and table saw alignment. The site is www.thewoodshop.20m.com and follow the link to How-To Articles. The finishing article is entitled 11 Great Finishes and Finishing Techniques.