We have a Burley Rock 'n Roll with a Softride beam for the stoker. The seat clamp goes around the beam, then it clamps the seat rails. There are plates on the inside and outside of the seat rails that have a groove in them to grab the seat rails. I would like to tilt the seat down just a bit, but the only way I can find to do that is by reversing the seat clamp on the beam because it looks like the inside plates don't spin. This tilts the seat down too much. As far as I can tell, there are just 2 tilt positions, and we are looking for one in the middle. If you haven't seen this type of seat clamp none on this will make much sense, but I am hoping somebody knows what I am talking about, and has a way to make smaller adjustments.
Thanks for any advice.

Tech info & downloadable manuals are still available on line:
https://www.softride.com/bikes/tech_guide.html

Going from memory, those clamp halves should have micro teeth that allow you to adjust the saddle tilt by about 1° (+/-) for each detent position. However, the last one I touched may have had a retrofit kit with later version of the mount.