Okay, maybe I can focus this on where exactly I am getting lost. The MCP4812 needs the data brought in a specific format. That is bits 15:12 are formatting information for the data and bits 11:0 are the 12 bit digital (or 10 bit ...) information that is being transfered.
As I understand it, the SEROUT command will send 8 bit packets and I am not sure how to get the cofiguration data combined with the actual data??????? and, combine this as 1 - 16 bit packet???????