Hard to put a number on how long it takes to break-in. Really depends on your driving style. From what I've been told by somebody who really knows his stuff is no less then 10K miles if you tow now and then. If you baby the engine could take as long as 20K miles or more.
On average, after 10K miles it should be fine to use SYN oil in a diesel engine. Thats what I did and my truck runs great! 16K total miles, City MPG 14, HWY doing 69 MPH light head wind 19.5 MPG (hand calculated) tail wind 21 MPG. Before SYN oil MPG was 10% less. My truck regens on average between 400 to 500 Miles, no ticking noise hehe.