I’m not John but I can answer your DVD audio question 🙂
Encode set to AC3;
Click on Custom tab;
On the first tab, set Dialog Norm at -31 (this sets it at unity gain);
On the last tab marked Preprocessing, set the Line Mode Profile and RF Mode Profile mode to “none”;
DC High Pass Filter On (this operates at <=3Hz and takes DC bias out of the mix);
Bandwidth Low Pass Filter On (this takes aliasing noise at >20kHz out of the encode).
Save this as a preset.