In working with the current platform tonight, I found that the USB audio interface is a limiting factor for signal processing - on the same processor. The buffer size is set at 48 bytes, due to the sample rate of USB FS and the audio sample rate. This is great for the USB audio interface, as the fairly latency is low, but between this and the short cycles between ADC transfers, effects processing is not ideal. So, the way forward now is...back to Linux, mostly.