You made the right decision, buy or build a proper stand. I am a professional cabinet and furniture maker, that dresser won't hold anything near 800 lbs. Make sure your stand is on solid floor and level.
I have made furniture grade stands for aquariums and other heavy things. Remember that the whole thing is still top heavy, the aquarium weighs a lot more than the stand. Some times I take the extra step of fastening the stand to the wall. A couple of relatively tight guy wires of sufficient size from back of stand close to top, fastened to screw eyes into wall studs or a sturdy pair of hooks and eyes, ( heavy duty "screen door" type hooks.)