Hello, I have read through the few posts about closing loops for structures along with any tutorials and still cannot get my inverse kinematics simulation to run. I am trying to simulate a robotic arm in a parallelogram configuration (picture below) and am running into two problems. The first is that the loop does not close or lags behind due to the tip-target relation, and the second is that as the arm tries to follow the dummy target, sometimes it flails around as it tries to find a solution.
There are two versions that I tried to run the simulation on. The first is a more realistic representation of the arm with more complicated shapes and 3DOF (one on the vertical arm segment and one for the horizontal segment, the third being rotational around the base).
Realistic Model

The realistic form follows the target, but the problem is that the parallelogram is not really closed as it just follows the closed loop as a tip-target relation. With the GSC overlap constraint selected it does not follow at all, simply the top portion of the arm moves. The arm also tends to jump around everywhere until it finds a solution that fits (The arm is NOT redundant). I have tried using non-damped, damped, and a combination of the two for the IK groups. Although this did help somewhat, it would be preferable to avoid the flailing all together.
The second version I tried was a simplified form using simpler shapes, and removing the third DOF (rotation about the base). I also removed one of the constraints in this version to make sure I did not over-constrain the model. This version still flails around as it tries to follow the target, and the loop does not close properly (the linked dummies for closing the loop are overlapped prior to running the simulation).
Simplified Model

Simplified Model Broken Loop Simulation

I have tried using a dummy-dummy links, along with the method of linking a spherical joint with a revolute joint mentioned in viewtopic.php?f=9&t=2979 with no luck.
I have also attached images of the scene hierarchy for both models as well. It might be worth noting that the tip-target following works a lot better when the loop is ignored, so I believe the closed loop complicates things
Realistic Model Scene Hierarchy

Simplified Model Scene Hierarchy

TLDR:
So my questions would be...
1. How can I close this loop to be like a regular joint (not a tip-target) that remains closed always?
2. How can I get rid of the flailing as the tip tries to follow the target?