I would think it depends somewhat on the width and volume of the board, but my 170 on a low volume pocket board will sit on its side for a long time. If there is no wind propping it up or it doesn't land perfectly side lying it eventually drops flat.
As to build, Have been riding the 170 pretty hard, no straps, lots of airs tho and it's a really nice piece of kit.
Stoked with it.