I tried the mending plate method idea last night on the gold bike. It works. Its really easy,talk about forgetting the bleeding obvious!

Therefore a dual drive mezzo reguires.
1.an extra cable to rout
2.a cable stopper
3. a quick plate making up to locate the frame clip.
4. the case of the click box removing if you use one.
5 a few cable tries to secure the last section of the cable run.
6. A bit of patience!

This results in a really nice bike. I feel if my black bike was but into production it would sell like hot cakes ,but what do I know. I can even come up with the idea of a simple plate! I am off to get some cake.