Yes – Sliding support of the platform is also possible with the triangular construction.
A triangular construction must have a fixed bearing “Static Support” at the top and a “Bracket” at the bottom. A sliding bearing is not possible, because otherwise the triangle would tilt sideways.
The triangular construction is in itself somewhat movable and offers some leeway for fluctuations, as the support rings allow some play.
If the trees fluctuate very much, there is a danger that the connections are exposed to strong tensions. The triangular construction must be decoupled from the platform: The easiest way is to place a sliding plate made of hard plastic (e.g. UHMW) between the beams and secure the beams laterally against slipping (wooden blocks or steel angles).