Check out this link from Superior Threads, talking about needles. Turns out you only need Topstitch needles - they handle everything. Dr. Bob know his thread and needles, his company depends on it. He'd make more $$ if he did like all the other companies and put out all the different kinds of needles, but he only recommends the topstitch for our home machines.
http://www.superiorthreads.com/shop/...s/description/