Congrats on the Audient and on the Matrix!
I have a ASP8024 36 ch. and love it. I thought about retrofitting the Dual Layer Control, but for the price (and a bit more) I'll buy the ASP2802 (now sold by focusrite) which will give me more 28 inputs (between other advantages). I'll than connect it between the send and returns of the 8 subgroups of the ASP8024 to automate them.
Having the Matrix it's a dream! Don't sell it... from the DAW go to the ASP8024, mix with it until you have your static mix set, than sub-mix (up) to 16 channels into the Matrix (use the 8 sub-groups outs from the ASP plus/or the any of 24 Tape outputs of the ASP). Than you can do the "Michael Brauer thing". (He dedicates one EQ and one Compressors to each one of his 4 sub-groups).
Let than the Matrix automate those analog (stem) subgroups (pos compression). You can also use the Matrix to automate Vocal sends to Reverbs, by sending the vocals to a fader in the Matrix and sending in to a Reverb.
The Audient is pretty much neutral sounding, so you are not getting any "color" if you put it summing after the Matrix.. also the big advantage in the Audient is the routing capabilities to integrate your hardware, so use them extensively and than let the Matrix put some of the SSL magic to the sub groups and automate them after compression.
DAW automation is good, but (for instance) if you are using outboard compressors in a vocal track, it's almost useless as the changes in volume in the DAW would change the amount of level going into the compressor and changing the amount of compression in the vocals, instead of changing the overall volume of the compressed vocal... so changing the Matrix for a simple DAW control only, isn't really an option as it would mean "going backwards".
Good luck and let us know the developments!