I have listened to people on here, watched Breakaway (again!) and come to the following conclusions for each mal...
Pilot Chute In Tow
I would wait to see if it clears itself whilst watching my alti and if nothings happened by 2000ft (I normally pull at 3500ft) I would cutaway and pull my reserve.
Horse shoe
In the event that my pin has come out before pulling the pilot chute (resulting in a horseshoe where the second point of contact is the pilot chute in the BOC), I would make one attempt at pulling the pilot chute, then cutaway and pull my reserve.
In addition to this, I now pack my pilot chute in a way thats recommended by Brian Germain.
Not so long ago I came accross his excellent method of packing a pilot chute, which has the potential to clear itself from a horseshoe mal (if the pilot chute is the second point of contact).
Using this method means that in the event of a horse shoe mal, the force required to extract the pilot chute via the bridle is alot less, which is why it has the potential to clear itself.
If it does not clear itself then this packing method still makes it easier to manually extract the pilot chute, even though the bridle is being pulled by the main bag / canopy.
See the following link...
http://www.youtube.com/watch?v=axCeYlY_6io