Flash the CSMKIII with the latest Grex compatible flash (pci kernel ver 2.2)
Install Grex4000D into your system (remove the original daughter-board and plug the Grex instead).
Make sure that the Grex is fully plugged into the CSMKIII expansion connector. To get a perfect fit, I used the two accelerator spacers from my Escom A4000T system which push the part of the CSPPC card closest to the expansion connector a few mm futher up, thus making the connection with Grex4000D very tight and well, unlike the regular sized accelerator spacers which will provide an "almost" good fit. It should work regardless, but I just didn't like having the Grex not plugged in fully into the CSPPC.
Plug in Voodoo 3 into a PCI slot and it should already output 4 colour display modes, such as the early boot menu, and CSMKIII boot menu. This would indicate a proper hardware connection and you are all set to install your Grex drivers from that point on.
