If you're not going to be using it in rough conditions, for high end events or sports I'd say the 1dx was generally overkill. Id get the 5d3 in your situation.
I, too, am an Amateur. Obviously as much as I post on here I cannot be too busy
Anyway, the mk. 3 is such a great deal financially compared to the 1dx. 6FPS is PLENTY!!
And with higher resolution, same AF, good metering, etc...it is a no brainer to all but the sports photogs that need dual processors, dedicated processor for AF only, ultra clean high ISO, and 14 FPS. In other words, about 0.05% of total Canon users. Get the mk. 3 and be happy you have one of the top 3 DSLRS on the market.
I too have been considering these as well ad a 1d mk iv. I am an ameature who likes BIF and (sunset or lightning) landscape photography. I can afford the 1dx and the 600mm is ii USM with gitzo/wimberly. Not sure I should, but kinda my dream set up. 600 has enough reach and the 1dx tracking, 12 fps and low light all seem fun to play with. My 1st dslr was a 7d. This would be my 1st FF. I wish it had f8 focusing since I plan to use a 2x with the 600 f4. I would ultimately want something wider than 35mm eventually and maybe a 50 f1.2. Maybe the 24-70, but I'd prefer a wider aperature.