Depends what is happening at the time. As you are probably aware the IFR departures from runway 21 route via the overhead (supposedly!) then towards DET.
Overhead routings are normally accomodated whenever possible. If the ATZ is busy then I would suggest south abeam, following the M25 if VFR, is the best alternative course of action.
North abeam is nasty due to inbound traffic on the ILS and outbounds who have missed the overhead
