XRAY - Model racing cars

The inner holes give less Ackermann angle than the outside holes.

Ackermann angle is the difference in angle between the front inside and outside wheels. When cornering the inside of the car needs to turn a tighter arc then the outside, so the inside front wheel in principle has to have a greater angle then the outside wheel to prevent unnecessary drag. Moreover if you get the Ackermann angle right then you will have maximum front end grip and thus steering.

For most drivers a big Ackermann angle (i.e. outer holes on the servo saver and/or front holes on the steering block) will make the car to aggressive and twitchy. Therefore the standard setup uses the rear holes on the steering blocks and the center holes on the servo saver. For foam tyre racing there are even optional steering block extensions to reduce the Ackermann angle even further (foam is much more direct then rubber).

Mostly we run the standard setting in Europe as we generally have fast flowing tracks. On tighter tracks you can consider running a bigger Ackermann angle (or more front toe-out) if you feel the car is understeering too much.

ducks as last post flies clean over head

That is beyond me
How about in laymens terms(english)