Depends on who your opponents are and what the strengths of your team are. Definitely agree with what rocket.science said about rebounding. Over the last several seasons I have compensated for my lack of good outside defense by outrebounding my opponents on both ends, and heavy use of 3-2 zone. Managing enthusiasm and GS better than your opponents is very important also IMO if you have a disadvantage in OD.
Ummmm, I still do not have either 6 players over 10 OD or 3 players over 15.
Good thing about OD is it is not too expensive salary wise, so it is possible to afford 3 players over 15 at the D. III level. For salary, JR is the real killer.