Two nice pcs. lots of possibilities. No replays are wrong, just different ideas.
I think I'd just use the lager pc on the right. I would move it out a bit from the corner and tilt it back at an angle with will hit the cut off top as Chad pointed out.
I'd cluster stems plants around the back & sides, maybe some crypts taking hold around the roots. I'd leave the left 1/3 unplanted to give hue contrast to the heavily planted stump side 2/3s. Basicly making a fresh water 'reef' around he stump.
Cool pics of Driftwood, looking forward to seeing were you go with this.