In my experience Di2 is not intuitive. The shift up/down buttons are arranged the same way as my single. Also, they can be reassigned in any arrangement.
Whenever we get on the tandem I shift the wrong way fairly frequently until I get used to it. This becomes less frequent the longer we are on the bike but I still find myself having to think about how to shift all the time. I can't think of another arrangement that would seem more intuitive to me.
Somehow with mechanical shifters, my primitive brain understands that shifting to a larger cog requires pulling a cable and shifing to a smaller cog requires releasing the cable. I can adapt to this on 4 different mechanical shift systems almost immediately and without thought. But I still have to think about shifting with the electronic system and often mis-shift. I don't know why this is.
The Di2 display has helped but it is not a perfect aid because the display for the chainrings is very small. I wear polarized sunglasses that are not bi-focal so I can really only see the cassette indicator and the battery status.
I'll be interested to hear how you like the SRAM setup.