Not sure what an "older Ventus" means but I have a B model and for it there is a pin for holding the air brake position while assembling; same pin as used for removal of water tank caps. Pull back the air brake handle until the hole becomes visible, insert pin in hole. According to my manual flaps should be set to S. Seems to work for me. I have found the help you receive makes the most difference in getting it together easily. Some people I have had assist me have made it a breeze and others turn it into a struggle. I just bought a single person rigging cart. I am hoping this can cut my reliance on random help.