So far I'm thinking the best connections are:

If Vmotor is the stepper motor's common supply point, derived via a high
power Resistor from +12Vcc,
(and each of the 4 coils' other ends gets pulled down to 0V, by the ULN 2803
o/p.)
Then the clamp diodes' common (cathode) pin will connect to Vmotor. This
effectively puts each diode directly across it's coil.

Paul B. said:
>  The common for the flyback diodes should return to a Zener of twice
>the supply voltage.

Is this an alternative to that above, or an additional protection?
Would I stick a zener across the 'common' and 'ground' pins of the 2803?

I've been watching the discussion closely, thanks for everyones input.

</Dave.V>