Can't rotate nested site family

[spm8C88E]

I know this question has been asked and answered many times. I've watched this tutorial (https://www.youtube.com/watch?v=cTGrJylG4Uw&t=301s)  but still can't get my situation to work so any suggestions would be helpful!

I'm modeling a bench with slats of wood. The slats are a separate family nested into the bench family. Both families are Site families. I've done this before, but never with angled elements. The back and front of the bench are angled and I can't get the nested family to align or rotate to the reference line or plane (I tried both). The nested wood slat is work plane based and always vertical is unchecked. See "cant rotate" jpg. If I place the wood slat family into the view it is rotated vertically instead of showing the end of the slat. See "place family" jpg.

Any ideas or tutorials? thanks 🙂

[ToanDN]

You HOST the nested family on one of the reference line's work planes, not just align to the reference line as you did.

[spm8C88E]

The second image is what happens when I place the nested family and attempt to host it on a reference plane. It is in the wrong rotation. Tabbing doesn't change the rotation. I need to see the cut end of the slat like all the others, not the long side. So far the only thing that sort of works is to create an extrusion following the angled reference line and hosting the slats on that and then hiding the extrusion. This seems like a fix and not the correct way to do this. I tried setting the work plane to the angled reference line, but it's at a weird angle so when I host the slat on it, it's also at an angle. JPG shows weird angle of work plane

[spm8C88E]

oddly I was somehow able to get it to work on the top half of the bench despite the angle work plane then copied the slats down to the lower reference line and picked a new host to get the slats to stay in the correct orientation. Still don't understand why the angle of the work plan is like that...