I'm running the 440 with my HDX, I buy just the NAV charts (from Jeppesen) for the 440 and it will fly the approaches just fine through the HDX. The obstacle data and charts I get from Seattle Avionics for display on the HDX - the larger screen size works to advantage there.
No, I use the standard Sandisk 32GB USB3.0 sticks. The small Dynon mini-USB's didn't last too long for me, I've had the Dynon system for 10 years in my plane. If you want the IFR charts and maps for all 50 states you'll need the 32GB size.
CPDLC!!
Controller-Pilot Data Link Connection - the ability to "text" ATC messaging back and forth instead of tying up the frequency. This is the way forward!
The Dynon also does not display traffic overlaid on the procedure drawing - so I do as Marc said, I leave the procedure up on my left (main) screen, and a zoom on the right screen moving map to about 3 miles for traffic near me as I'm on the approach.
I have 5 USB's each cycle for 3 airplanes with the SA charts and Dynon databases. When I plugged the first USB in and got the "Cannot read USB" error, I naturally assumed a USB failure. Then the next one, and the next. 5 out of 5 failed and I knew I wasn't looking at all my USB's going bad all...
I had the same issue, and another local pilot did as well. Seattle Avionics will now download the Dynon database onto your USB stick as well as your normal subscription - but this latest cycle it was corrupted. If you'll download that file direct from Dynons site it will work fine.