Spellmaco Transfer punches seem to be the best I've seen and used. My import set is not accurate, so I keep them around to fill out any odd diameters.
McMasters sell individual Spellmans in all sizes in metric, letter, number and fractional, so if you just need one particular size, you don't need to buy the whole set. I have the Spellmaco fractional set with individual metric and letter sizes that I use. The imports are usually way undersized and not hardened. I found my vintage Spellman set on Ebay for $30.00