Keet's guide at https://www.dodecagon.nl/dodecagondocuments has helped a lot here.

Nice to hear that you found them useful!

I have two levels which have a continuous slope (the roof starts mid 2nd floor and continues to 3rd). Sloped ceiling works but very inconsistently and currently only at the topmost floor. Hoping for someone to have met this challenge before

If it is the ceiling under the roof I would suggest that you switch off the ceiling display and use the roof generator to create the roof. That roof has it's own 'ceiling' because you can texture the inner side of the roof. In some situations you will need the inner side to have different textures over different levels. In that case you can add thin partial roofs under the full roof and set the inner side of the full roof invisible.

Personnaly I consider the sloping ceiling an old feature that was needed when we didn't have roofs with their own ceilings. Does anyone have an example where it really is useful considering the alternatives we have with roofs and/or other objects?