I also just finished the installation of Phil's bevel box mounting bracket. I can attest to all of your findings.
The other upside I found was that evidently the original bevel box mount was not mounted straight in the car and as a result it was almost impossible to get the belt to track in the center of the rear pulley no matter how I adjusted the rear wheel.
Phil's kit straightened out the bevel box and now the belt runs true and is easy to set up.
A great guy to work with and his products are excellent.
Excellent products and fantastic customer service.