Is your king an adult or hatchling?
If it's an hatchling you must start small if it's an adult so long you can provide proper temps (and that will be the hardest part in a large glass enclosure) it's fine.
Does it need something that big, is it gonna be easy to heat, or clean? NO but again if you are aware of that I don't see an issue, unlike BP, Kings, Milks are not prone to stress.