TopCat

The book I used years ago is out of print now, if I remember correctly. But there are several on the net. Check out amazon.com, do a seach on "sheet metal layout". Some are pricey...$50.00 and up but are worth the $$$. The cone you mentioned is simple as it is a concentric cone. Square to round gets a little fun to lay out but really not that difficult. I know this may not be exactly what you were asking for but I don't think you would go too wrong with one off of amazon. One idea you might try is to find a sheet metal shop in your area and ask to see their layout books. Most any large air conditioning place will have a sheet metal shop to make their duct work.