Great questions Steve!
I wish I had a 710, so I'm not sure I can help. The DRA should use
audioin/audioout/ground/ptt
connections.
Rig should be on 144.390 in the United States, no offset, no tone
(especially not ctcss 100hz),
FM modulation. Adjust mic-gain to taste by comparing how loud you are
to other stations.
If using the speaker output for audio, adjust the volume knob so PktLog
reports volume levels
between 20 and 80 (50 is ideal). There's a vibrant blind-hams
community of which I'm sure
you're already aware, and a few on this group.
if it helps,
-craig
KM6LYW