Topless it just looks better and less maintenance the glass tips just get dirty, get the moisture build up on them and hold back the light.
Also just curious what did you put styrofoam under the tank? The tank is designed as to now have anything under it. The weight is distributed on the 4 corners. If you have something underneath it and it's not resting on the corners you may damage the tank. It will push the pressure outwards instead of letting the corners do what they were designed to do.
If you look at tank stands for the most part the centers are empty.
Some tanks stands have a top so to speak but you don't wanna put anything between the tank and the stand. You can cause undo stress to the tank.