Accidentally found a neat single wiper system for the project, the same part is used in E36 BTCC race cars. Before you ask where to get one, here's the part number: Fiat #77998170. It has same spline/cone angle too to fit orginal wiper arm.
This is much more simple and lighter system than the modified orginal I had earlier.
I was inquiring connection rods earlier this summer, some were too expensive and some cheaper ones seemed to have a bad reputation. One day I noticed SPA Turbo makes conrods too, I had only heard their cast manifolds are great quality, but soon found out lots of their products are used in South America racing scene.
I did contact them to ask if they have BMW rods, surprisingly they promised to make me a custom set of Super-A beams
Just got the file and this is how it supposed to look:
Didn't take too long when I had already 3D printed the part for mockup: