How to set gains with DD-1 with a MS-8 supplying two amps?

[mdhurtubise]

I just got my new DD-1 and I'm a little confused with how to properly use it with a MS-8 in the mix.

I'll give you my setup so you have all the info for my question.

I have Sync 3 system with a modified "As-Built"  in the ACM to supply af flat line level out (approx 4 Volt preamp out).  I've disconnected the factory amp and speakers and disabled the EQ from the sync 3.  I've tapped inthe the front and rear speaker wires before going into the factory amp and now have the flat line level output. 

Sync has 30 volume notches:
25 - 1.79 Volts
26 - 2.07 Volts
27 - 2.39 Volts
28 - 2.68 Volts (perfect for JBL MS-8 which is based on 2.8 Volts)
29 - 3.12 Volts
30 (Max Volume) - 3.49 Volts

Im running a two JL Audio amps (XD1000/5v2 and XD800/8v2). I also posted my wiring diagram and setup info in this post.

When calibrating the JBL MS-8, I've been sticking around volume notch 25/26 which gives me the OK OK OK signal. The question I have now is how do I set the gains properly with the DD-1 on my two external amps? Do I set the gains to low and turn them down all the way counterclockwise prior to the MS-8 setup/calibration and then use the DD-1 post MS-8 setup/calibration to set the amp gains? Or vice versa?

System Wiring Diagram.docx