The size is ok some people like smaller bowls some like smaller ones (I do) the only thing with those is that sometimes the snake gets under it and then tip it over, no big deal just a big mess.
It is really hard to prevent them from tipping their water dish (sometimes it seems that it is all they have in mind) knock on wood so far the dishes I have been using have never been tipped………….I use those http://www.pet-dog-cat-supply-store....p-flypage-9736