My redfoot sometimes does that. I always find it disturbing when he even sleeps in his water.
You might also try to spray him more and see if he soaks less, or perhaps he needs the temp turned down just a little???
My solution for the suction cups that wouldn't hold was to throw them away and the plastic as well. I used a tie wrap to attach a magnet and then had another magnet on the other side of the glass. The magnets they sell to clean algae work really well.
I think it mainly is determined by the stand or support that it holding up the tank or that the tank is resting on. For example a flat surface would be better than a stand that just supports the edges.
Rocks are nice in the tanks, but they scare me that if you fumble or slip with them while...