You probably thought after reading the title, that I'm being extra nice, and you would be right!
I am being extra-nice because it is extra-important that some extra-ordinary person could find it in themselves to provide a tutorial patch demonstrating how to set up basic but efficient duplex operations, something that demonstrates how to record to an SD card in chunks while simultaneously playing from one, stuff like that. I read somewhere it can be done though clever, efficient patch work, but there's nothing out there to actually demonstrate it, no patches.
If anyone has a successfull patch they're prepared to share, please do!