[Arran]

The main issues I encounter with dial cords are that it is either rotten, and snaps, that the cord is stretched, or that someone else had a go at replacing it and fumbled it. I've replaced dozens of dial cords and have never had to use rosin on one to get it to grip around the control shaft, there is a certain logic with how they are routed that is harder to describe then show.
I think that your mixture may be a bit thin, one tablespoon is equal to two tea spoons, so that mixture is 3:1, I would think that 1:1 might be closer, but it will take some experimentation to figure it out.
Regards
Arran