my experience with only 2 OWE tkts:
1: hand written by a DTW airport AA agent. once it is less the n16 segments it can be changed from hand written to computer printed if you need reissue in the middle of the travel.
2: computer printed as two ticket that cross referenced together by CTO in Auckland. The fare is divided into half among 2 tkt numbers but it can be printed.
I am gonna do my third one ex UK/Europe in this summer with opendate... donno how it gonna be this time..(I think I will use AA since they seems nice to an EXP)