I would recommend looking into the second hand market.
eg.
Crown CT Series (DCI would also be an option, but not cheap)
Powersoft Quattrocanali / Duecanali (maybe the older series before Powersoft introduced the DSP+D models)
Regarding the amps you mentioned, I only hand my hands on the t-racks DSP 4x4. I tested it once and i did not like the signal-to-noise ratio = too much hiss. At least for the application i was looking to buy the amp for. Definitely an issue with high sensitivity hf drivers.
To make such a multichannel setup work properly you want the possibility to apply EQ and Delay to each channel. External DSP or amp with DSP on board. If this project is a permanent fixed media installation there are maybe cheaper options, doing the processing with software in the playback computer.
For spatialisation have a look into L-ISA studio if you havent decided which tool you will use. This software works great, even with non l-acoustics hardware.