I'm fitting wasted spark onto cosworth ignition on a dax rush and the 'normal' setup used by Motorsport Developments (who provides the board to go in the ecu to convert single coil to wasted) is to fit a second cosworth ignition module. lack of space means I'd like to know if there is a similar single ignition module which runs dwell control for two coils.

the normal cosworth module controls dwell because the ancient ecu only provides an earth ground to say 'make a spark' and almost immediatley after, it starts to charge the coil again thus attempting to maximise the coil charge for the next spark. The module limits current when the coil is saturated.

yep there is a solution its called megasquirt