$GPRMC, $GPRMB, $GPGGA and $GPBOD (when I tried to use $GPAPB rather than $GPBOD things got messy).
Hope that helps. Works well, CDI and/or HSI have always seemend correct with this combination of sentences.
I guess if you're trying to drive both the Dynon and Trio, you'd get away with it if they could both live with the above 4 sentences.
Oh one more thing to note that just popped into my head from when I set this up a few years ago... When I first hooked this up I had a standard cable. Make sure the only pins connected between the iFly and the D10A are the ground and Tx from iFly to Rx on Dynon. If the Rx from the Dynon is connected, the iFly 'receives' a signal, thinks there is some other device attached and things go haywire. It was a long time ago so I forget quite what bit suffice it to say the neither device was happy. What I chose to do since the DB9 from the Dynon is the same one used to connect to a PC for updates etc, was to clip the offening pin off of the iFly USB to serial cable so that it physically couldn't receive anything the Dynon was putting out and get confused.
Regards,
Alasdair