Finally got out this weekend for our 2nd ride. A correction: I stated earlier that our chainrings were 53t x 34t. This is incorrect. They are 52t x 34t.
I updated the software on the Di2. I increased the display time on the gear/battery display from 5 seconds to 120 seconds. This makes the display more useful.
Based on recommendations here our recent ride went significantly better. The two suggestions I tried were: ride mostly on the big ring. Use the small ring only for climbing hills we can't handle with the 52t x 36t combo. This helped significantly. I was able to concentrate on shifting the rear derailleur only. The other suggestions was to try to train my brain to shift correctly. Someone's suggestion to use the mnemonic device "smooth is smaller" helped me shift the right direction. I mis-shifted only about 10% of the time (instead of 50%).
These two things permitted us to enjoy the ride much more. What we were able to appreciate more was how smooth the ride was compared to our old steel bike.
I'd say the main complaint I still have is the big jump from the big ring to the small (52t to 34t). This is a huge drop. I would have to think quite a while to try to plan this shift & still did not pull it off well. One way that I think I can improve this is to call out to my stoker "downshift" so she knows our cadence is about to spike and maybe able to ease up on the torque a bit. If I can figure out a way to upshift the rear a bit at the same time that I'm downshifting the front, this may smooth the process considerably. I have read that "Synchroshift" is available for the XTR version of Di2 - but not for the road versions. Is this true? If so, does anyone know why? I would think this would be a feature that could significantly smooth out the shifting process.
Also, based on recommendations from AKExpress, I have ordered new chainring sets from Praxis: I got one set at 52tx36t and one set at 50tx34t. In one case we would give up a bit of bottom end & the other would give up a bit of top end. I have not yet installed either.
However, even with our ring span within the Shimano recommendation of 16t max, I think it will still be a big jump from big to small (or the reverse). Have others here developed a technique to make this jump smoother? Our old bike was a 54t - 44t jump. I had become accustomed to this smaller jump.
Thanks again for all of your experience & help.