For Knights it might be better to use Scout Bikes, the Impulsor is relatively tough, but not so tough it can just shrug off a Knight, even if it has the 4++ the feet will do some serious damage.
Scout Bikes are easier to hide and can be moved out one unit at a time, right up to 4" in front of the Knight in your Movement phase. They can block and absolutely huge swathe of board if you space them out, even on a bowling alley you'd be able to block your opponent from moving forwards. Bikes can also surround a Knight and prevent it from falling back.
You need to be aware of which of your enemy's units are Characters if you want to body-block, even if you don't do any charges your opponent can still heroically intervene.
|