Only use a floor-to-ceiling tree beneath a sloping ceiling if the manufacturer explicitly supports that arrangement for the model you choose. A flat contact plate should not be tilted or packed with improvised wedges to imitate a suitable connector.
Some systems offer a dedicated component for an angled surface, while others are intended only for a level ceiling. Ask how height should be measured for the approved configuration and whether mechanical fixing or extra support is required. The slope may also reduce space around the highest platform, even when the pole can be secured correctly. Check the cat's headroom and its route down. If compatibility remains uncertain, a freestanding tree of suitable height may be easier to plan. Choose the product around the room's construction rather than trying to force an unsuitable installation into place.
An angled connector is a model-specific component, not a universal accessory. Obtain its part number and approved slope range, if specified, so you can match the actual ceiling rather than buying a generic-looking joint.
For product comparisons alongside this advice, see Feline Sovereign Spire and Modern Vine. The details below explain their sizes and uses.
Further reading: .
Feline Sovereign Spire
Modern Vine
SkyRoute wall climbing set