hmm they are both awesome iwagumi, but I guess I prefer the second one if you could tweak it a bit. Slope the substrate a lot so that the rocks are up higher, and then slope it from left to right a bit so that the main rock is higher than the secondary one. For plants you could do the perspective style where you have stems against the front glass and small plants back farther. Maybe glosso in the front fading into HC so it would look like a mountain in the distance.
But if you do go with the first layout I recommend some kind stem plant in the back, maybe bylxa as it would radiate out like the rocks.
They are both great layouts and I can't wait to see what you do with them and the nature aquarium tank. It's not often we see NA style so I am especially interested in that tank. Have fun!