[Sugarnutz]

Some of this post is for future reference for others as to what can be done but glean what you can from it.

I'm kinda doing what you're doing for a dedicated remote tracking rig, I'm doing PCI-x in a Magma chassis with HD Core and 5 Accel cards (because that's what I got, not necessarily what I need). You've already got a setup that major studios have used for years in the 3 PCIe Accel cards and i92's. I have several 192's, both digital and analog, nothing wrong with them. I also picked up an Apogee AD16X-192 & DA16X-192 for reasonable along with a Rosetta 800-192. I'm on a 2008 Mac Pro 3.1 I got for real cheap like $120 cheap, upgraded the processors to 3.2GHz ($75) 32Gb RAM ($100) and a nice modern video card that will drive a 4K monitor ($300).

As far as plugins go you can still download Waves 9.3 which is the last version that supports TDM and right now you can get Waves Diamond bundle for $250 or less. You have to install your licenses using a newer version of Waves Central on a USB stick using a more modern system and then install the actual plugins using the 9.3 installer. Just instal the plugins, don't mess with your licenses using 9.3. I have an extensive Waves collection and most will work on this system. I'm running Pro Tools HD 10.3.8 which is recommended for Mountain Lion 10.8.5 and one of the last versions that support TDM. A lot of my other plugins have 32bit AAX versions that will also work.

It's a lot of work getting it all together for an older system like thee but they were workhorses in their day and still can be for some tasks. My main setup is a Mac I built with i9 9900K/64Gb/8Gb Video/Mojave/Pro Tools 2019.12 Ultimate/Avid TB Native/D-Command. I don't really want to drag any of that out of my home to track which is the way I work. I also have a 2015 MacBook Pro which can hold it's own with a lot of desktops for running Pro Tools. Options today are pretty much unlimited and your system & direction is a good one. Good Luck!