Unfortunately I forgot to select the option to get the solder stencil cut to size. So It was quite uncomfortable to work with. And on the first Board it often slightly warped away from the Board an caused solder paste leaking around the pads. I tried my best to hold the stencil down with my hands but one corner would always eventually lift. To combat that I laser cut a small U-shape from Plywood to have a more easy way to hold the stencil down. With that I experienced no more leaking solder pads.
Probably I was just reinventing the wheel. Nevertheless, with this thing I managed to solder the second board and it turned out perfect except for two little tombstoned 0402. And there it is: