The "break in" instructions should be in the handbook. It goes something like this, First hour no more than quater throttle, second hour quater throttle with the occasional half throttle, 3 to 5 hours run at half throttle with an occasional 3/4 burst........etc etc.
Don't take that for gospel though, if you can't find the manual for it, give Barrus a phone and get them to tell you what it should be.