Honestly, I have no idea how much rock is in there. The totaka weighs a lot less than fiji, so probably not as much weight as it looks like.
Yeah, your rock is a lot different. I'm a fan of more open aquascapes, as opposed to the wall of rock. Of course it will look good once corals are growing. Maybe you could try a pile on each side, and open in the middle. Or a big pile on one side and have that taper off towards the other side with maybe a smaller pile there. Or just place that huge rock on the left by itself on the sand. I know it's hard in a 45 though.