@jooshewa I grow two Oeceoclades outside here in central Florida. O. calcarata and O. maculata. Calcarata is slow but consistent and maculata is pretty much a weed, popping up wherever there is fallen leaf cover.
O. calcarata growing with the succulents. Note the skinny leaves indicating a high light plant
O. maculata outside in shaded walk areas.
The leaves are reminiscent of Sansevieria leaves, just not as thick.
These seed pods are probably why this is so rampant. Every flower makes a seed pod.
If you have your heart set on gracillima try contacting Out of Africa directly. Although not listed for sale they likely have it as they specialize in African and Malagasy plants.