It wont cost much to get the 2 shafts for the chain coupler  style . I would need to go look if they are a hex shaft all the way to the bearing and pulley on the left and the sprocket on the right .  If they are it ,  would be very easy to do .  Also be a where that for a older combine on a 900 series head there is a larger pulley available to drive  the knife .
The dial-a-matic will  work with the correct adapter . 9 pin to 16 ? . Dont  remember