Paul Sobon's T2 proa PROAZAK at the Jersey shore.
Installing the hinge between the first and second deck boards allows the platform to swing up while the rig is up. This allows one to stand between the iakos and lift the whole boat at the balance point of the vaka and ama, which is about 10 inches outboard of the gunwale. The whole boat, sails, oars, paddles, etc. is about 150 lbs. so single handed launching is straightforward.
The dimensions of the lashcap legs and the gunwale bracket risers add up to slightly less than the depth of the iako. The gap allows the stress generated by the iakos to be born by the lashings instead of the wooden fitttings. The lashings are checked periodically and tightened once or twice a season.
Paul decided to hinge the end of the oar stanchion after two mishaps. He uses two oars when singlehanding. Twice, when sailing fast in rough conditions, the stowed non-steering oar bounced into the water. The pressure on the oar produced enough torque to tear the stanchion off the boat. Alarming to say the least.
And yes, it all fits on the roof racks. Lots more photos and details here.