Pemberly - I don't remember - how old is your kiddo? If she isn't too far past it, have you considered putting her through the Wilson Reading Program? It breaks things down in a logical way that helped my son a lot with the logic of spelling ... at least for the words in the English language that follow logic.
As I said in my first post, I wouldn't put hours into practice. It seems the older they get, the more that is absorbed and retained, so driving them crazy when they're young doesn't seem all that productive when there are other things that need addressed that could use that time to better use.
My husband is in his 40's, has had two successful exits from companies he co-founded and is now on his third startup. He still asks about spelling and relies a lot on spell check. It has in no way hampered his success. He's developed business plans, had to communicate with venture capitalists and angel investors and is very good at communicating.
