Having read Conway's books, I would say stay away. I would also stay away from Buckland personally, his books are full of lies and misinformation. Grimassi has also pulished some rubbish, but has some redeeming works to his name.
The issue with dragon magic is that it is a new path, it is an eclectic path which utilisises techniques and traditions of other paths. If any author is selling that dragons are all beautiful, benevolent creatures, stay away. With the exception of some Asian mythologies, dragons are not benevolent and are even said to despise humans. They are wise tricksters, of course some of us, including myself, find the misunderstood fascinating.
My advice is to research myths surrounding dragons, and simply use the standard theories of evocation and invocation tailored to your needs through the information which myths give. That is, see what offerings dragons would like, see what services they can perform, what they mean spiritually to you. These sorts of paths are largely individual, and it should be your own technique you use. Not Conway's fictional dragon language nonsense, but actual, legitimate craft.