I have 2 mechs and 2 bikes. Fusion terminator(DH duties) Giant STP (dj 4X duties)
Long cage X.0,  Short cage X7

I have a dilema on which one to put on which bike though.

Do I:

A. put the X.0 on the Fusion and the X.7 on the STP

B. Put the X.7 on the Fusion and the X.0 on the STP.

What do you guys think would be ore suitable?

Cheers,
Lewis.

Yeh thats exactly what I was getting at bud, I can't see the performance of an X.7 being that inferior to an X.0 for dh?

Yup, X7 is a actually a medium cage (they only come in long or medium).

As above, ideal would be to get two super short x9's if your running single chainrings on both bikes- about £100 for a pair.