Carlos, I ended up using an old ball joint front shock bushing between the mounting bushing and the fiberglass. I think I zip-tied it to the wiper assembly.
I got a set of the older arms(which are 9" both sides) and some 10" blades. The arms have a smaller inset for the aluminum nuts. Looks like the nuts on your mechanism. I took the blades apart and painted nuts, arms, and blades in hammertone silver. I don't think that long arm will work that you have. Also, I had to bend the passenger side about 20 degrees to make it rest near the windshield base.
Who did the wiring on that, looks very sanitary! No relay needed, just a switched ignition or accessory lead. I have it on a 15amp along with the horn.