What shifter do you have, or plan to use? Are you currently index shifting?

The shifter determines indexing and would affect the rear derailleur selection. Do you plan to keep the current freewheel?

The current routing in the OP pics looks very unusual, as if the actuation ratio of the RD is being increased. Stock routing for this RD (Position A in the pic below) should be about 1.7/1. The pictured routing is similar to the way some RDs can be used in a manner that emulates a higher actuation ratio RD, (see below), only this is more extreme.

Routing at Position B is used to get a higher actuation ratio that is similar to older Dura ace (aprox. 1.9/1).

See Sheldon Brown's Dura-ace page for details.