Bunkers:
sculpt them deeper. Flatten seems to work better than raise, IMO, so everything is more even/less extreme.
If you use stock shapes, use the same shape, make it a little smaller so it's only the sand that gets lowered.
All blue brush stuff.
OB:
Can't remember the menus off-hand. But on the right, where there's Create Surfaces and Place Objects, etc, one of them has a bulldozer or something, and in that one is the options for placing OB. It's in an odd spot, IMO. Notice when you place OB, to remove it, you have to hover over it, and there's a button to delete it.