Difficulties with PhAT collision boxes

I’m having a couple of problems trying to set up a physics asset file for a skeletal mesh. The first is that I am unable to scale the collision boxes below a certain size. There seems to be a hard lower limit to the box size that’s much too large for the bones being targeted. The target bones are comparable in size to leg bones on a typical player model, so they are not unusually small.

The second problem is when I try to simulate the physics, the model explodes. I have tried several times to turn off collisions between the elements and have also tried welding with no effect. Even if I have just two collision boxes that are spaced well apart, the model still explodes.

I thinking there’s a setting I overlooked or the import did something wrong which is creating trouble for the physics. The model looks and works perfectly with it’s animation otherwise. I just can’t get PhAT to behave.

Ideas?