After reading all the documentation I can find, I remain confused:

Is the Mach Pulser driver still required, if you are using a Grex over Enet?

Is the USB connection to the Grex required of Mach for operation, or just initial firmware download and setup?

How critical is the interrupt latency as reported by the Pulser testing program, when using Grex over Enet?

I realize the Grex/Mach connection is a work in progress, but these are architectural questions that surely must have answers by this time. I note that the Mach demo program does not behave itself completely without the driver installed. But it seems like with Grex doing most of the time critical motion control, Mach just needs to service it every so often.