Well, by way of contrast, this point in the original book took us up to page 121 of 309. The story is currently 44,000 words which is approximately half the length of the average novel. However, we still haven't seen any deviation from the original story which suggests that Harry's opposition will be much harder, so I'm inclined to go with the first estimate, which gives us about 1/3 of total length so far. Not counting any sequels, of course.