FWIW I did spend days (weeks?) reading the fare rules from EF and using ITA Matrix to construct itineraries, during which the fare rules were changed (they removed the ability to do stop overs) and the fare was gone for a couple of days on Nov 4-5.
Yet I still made some mistakes/mishaps, mostly due to (potentially) incompetent AC agents. I could have chosen to fly UA metal across the Atlantic sea, so that I could experience business cabin from AC/LX/WK/UA in a single itinerary, but I didn't realize it when I made the booking. And within the 24 hours of free change period, I couldn't get an AC agent to price the exchange to UA metal properly (there were availability in P-class but they somehow couldn't price it on that, have to bump it to Z-class and want to collect $300 from me, I ended up declining the change).
So yeah, if you have a TA you can work with, that would be the best, they can do the ticketing and exchanging for you, and they would be much better than regular AC agents that one can get (even as SE). The only caveat for me is that I have thousands of AC vouchers to burn (well, so do many other SEs who run for 300K/350K SQM target), and I'm forced to make my booking through AC if I want to use the vouchers.