Sauzo, This is what works great for my snakes: I size my soaking bowls as if they are hides, maybe you did too, I can't tell. And I believe it makes my snakes feel more secure, plus they can easily see 170 degrees and another 90 degrees with a slight turn of the head. This way they always know what's going on which is a good defense or for ambush. They also use the bowls even after they have splashed all of the water out.
That's why I believe the bowls are dual purpose, soaking and as a pseudo-hide.
I also believe the round shape helps with feeling more secure than the RB hides.
Mack
Butch
Elvira
Lizzy on the bottom, Mack in the middle