Good question! I haven't found any drip tips the correct size. The included tip is just too damn stumpy for my liking!
I haven't found anything that's a direct fit... BUT... The honest truth is, the bore of the chimney is just BARELY larger than a standard 510... I think it measures like 5.8mm or something like that? So to be completely honest, if you don't like the included tip you really aren't sacrificing anything by using the adapter.