I have been growing pseudolithos seeds along with several others ascleps with reasonable success. My medium is corase cocopeat containing short fibres which lets the medium breath without letting it dry out. The seeds are nominally covered with the same material and spray the top keep it moist till the seedleaves push up the real actor to come forth.Right from the start the seed trays are exposed to lots of light and breeze which prevents etiolation and good root formation. Transplant the seedlings in a mix of leaf mould with coarse sand. The seedlings should just sit on the medium with only the fibrous root being burried. once they start plumping up gradually reduce watering to prevent plant loss.