I gave the TC4 4* c-hubs a go today. All I can say is I'm very impressed
I compared them against (with std yok hubs) :
running the link on the top of the hub and using the lower hingepin hole
And running the link on the middle of the lower holes, also when using the lower hingepin hole.
The first option was quite sluggish, encouraged bodyroll and was slow to respond.
The latter was very twitchy, not a lot of cornerspeed and overall hard to drive, but fast.
With the TC4 hubs, the link angle was as if there was an in between with the 2 other options. The car was very stable, easy to push, lots of cornerspeed and was not lacking in steering at all.
All this testing was done on a small, carpet track with a front one-way. The reason I didn't try the upper hingepin hole on the hub is because I know this to make the car very aggresive mid-corner, more suited to Japan's tracks.
I suggest you give these hubs a go, and they are more adgustable as they come in a wide range of castor angles! I've only tried the 4* ones so far....