Control arm long, short? Curious

[Angusbeef]

Pictures found on google as reference.

Is there a reason for going one way or the other?

The black car has one side of the control arms mounted back much further than the other car.

Just something I've noticed and have been curious about.

 

[Rockwood]

Wider/longer will put less stress on the rear heims/tabs from impacts.  This is offset by the arm requiring a bend in it to clear the tires when turning, which makes it weaker (even with a cross brace to support the bend).  Geometry-wise, not much changes other than you need more offset to get caster with the shorter/narrower setup (since the upper heim isn't nearly straight forward, you have less adjustability in its threads).  

The shorter setup will also make it so the bolt ends aren't in the crash zone for your legs.  The bolts on the inside of the cab look painful if you smashed your leg into them.

 

[Sandkist]

The shorter setup will also make it so the bolt ends aren't in the crash zone for your legs.  The bolts on the inside of the cab look painful if you smashed your leg into them.

Not to mention the end of the A arm impacting your leg if it is sheared off