It wouldn't work for my Chrysler either.  It has separate shoes for the
parking brake, the rear disks are just for regular braking.

The angle of the handle is irrelevant. It's the number of clicks that
matters.

If the number of clicks needed is eight or above, then the cables
probably do need to be adjusted.

However...

-- Make 100% certain the parking brake cable ends are pivoting properly
on the calipers' levers. This is critical.
-- Make sure you're NOT using aftermarket pads.
-- Make sure both pistons are moving freely in their bores.
-- Make sure neither the calipers nor the pads are seized.
-- Make certain that BOTH parking brake caliper levers rotate when the
handle is pulled, and that BOTH wheels are held by the parking brake so
that you cannot spin them by hand (if one is still spinnable while the
other is not, then something is seized somewhere).

If the above five items are proven to be true, then:
1) back the cable adjustment off so that both caliper levers are sitting
against their pins;
2) then adjust the cables so that the parking brake takes six clicks to
fully hold the car on an incline.

With the cables thus adjusted and the parking brake OFF, BOTH rear
wheels should spin freely when spun by hand. Both wheels should
conitinue to spin when you stop pushing, and should spin about equally
freely. With the handle pulled up, neither wheel should be spinnable by
hand no matter how hard you push.