when you fly FFF you want to hold the model at that mark, at the top of the frame is fine and the model should settle into a 45 degree tilt forward stance and sit there. the more you want to hover, the more you want cg to settle in the middle of where all the arms intersect and at that point it should sit flat. discos hover weighted the other way just fine, but i mean hanging a bigger cam or more weight, etc to hover you'd want cg more centered up as a general rule. Too far forward in forward flight it'll go up and down like a ball bouncing down the road, too far back and it'll try pitching up at some sort of speed