I heard back from Dual after 3 or 4 business days and they advised the following for connecting the Dual XGPS170 to tablet with iFly (which worked!)
1. Dual GPS must be set to" ADS-B" mode. Setting is to "GPS" mode will not work.
2. No "helper" app is required iFly software, despite how the Dual instructions read for connecting it to Android devices.
3. Finally, as Brian stated, with the iFly app open go to MENU => ABOUT => CONNECTED DEVICES, and select the Dual GPS. The bluetooth connection will be made at that point and GPS soon to follow.
Thanks everyone for the suggestions.
By the way, the app and receiver worked perfectly on a recent IFR trip with plenty of IMC and a little weather to work around. Was very comforting to have good weather data at my fingertips.
One suggestion for iFly... instructions may be available here and I missed them but it would be helpful to have explicit instructions available for connecting the Dual XGPS170 to iFly app on an Android device. Especially since the generic instructions Dual sends with the GPS don't work for the iFly app.