Lots of talk about the bars in plan view (top down) but what about from the side? The bars together form a link with the instant center at a point where lines projected from the two bars as seen from the side, meet. Adjusting the instant center is why four links have so many positions.

Remember the GM A-bodies with their four links that put the instant center too far forward, rear end would hop on acceleration, embarrassing and making for very slow 60' times. The solution was to move the rear arm mounting point on the axle up (no-hopp bars) to shorten the the IC.

Even if I explained this poorly, it is important to get the bar angles so the rear end will plant.

R.