The driver for ixMicroTwinTurbo can be downloaded as 4.0.6 and 4.0.2 below.
The driver seems to be different for Macintosh clone and PM9x00.
Unfortunately, trying to download from archiveorg fails, so you have to look for a driver.
SO, I finally got ahold of a decently priced ix Micro TwinTurbo 128M8 graphics card. (thought I had picked one up previously, but turned out to be a ix3D UltimateRez)
I'm having some issues with the drivers. I initially went hunting in a few places including MacintoshGarden, as well as: https://eshop.macsales.com/tech_center/index.cfm?page=other_ixmicro.html&title=Other | IXMicro and http://system7today.com/drivers . Originally I went with the last version released (v4.06), but I would just get both extension and control panel "X"d out at boot time, and MacBench scores confirm
The ribbon cable was disconnected. Also made sure all the other connectors were snug and boards properly seated. Then powered it up and I get an arrow followed by the blank disk with a question mark. So, working as expected sans hard drive.
Downside is that I am pretty sure it only has the base 4MB of RAM.