I have the amas on my Oasis tandem. I leave them in the up position all the time otherwise they drag too much under sail in heavy winds. My friend with an ama kit had his crossbar tear off the kayak last week, but the wind was probably 15mph and they're really not designed for that much. He cannot get his hands inside the kayak to place a backing plate so has to rely on the rubber grommet nut thingies. He reseated the brackets using a marine sealant in addition to the grommets.
The sailing kit may not be designed for 15mph wind but it's still a lot of fun at 25 or 30 https://www.youtube.com/watch?v=3Rz3li-RZLI
I bent my mast on this outing and broke my crossbar in surf on another. I have the amas in the down position here, since then I have reinforced the mast, moved the amas to the upper position and stay away from surf!