You would need a lot more than just a piece of hardware cloth sitting on top of the tank. It would have to have at least some sort of frame. But really, using anything without some sort of latch for a tokay is a disaster waiting to happen. They are not just strong but also extremely smart and able to squeeze through much smaller spaces than one would think. If you're set on building a lid yourself, keep in mind that tokays require high humidity and anything made of wood will require moisture proofing in order to keep it from rotting or warping over time. Also, I'd use 1" x 2" lumber and more than just glue to hold it together. If you're not capable of building something properly, why take the risk of building something that's not substantial just to save a few bucks? It doesn't have to be fancy, but you do want it to be secure and not something that's going to be a worry over time. Also, you didn't say what size the tank is, but adult tokays require a very large enclosure to maintain a proper quality of life.