Dillution should work fine. You are already passing at home tests. You are not going to give them your morning void so don't worry about that. Practice again today using an afternnon void, dillute with about 40 oz of water. If you pass that and you should you are ready for the lab. On Sat. dillute with 40 oz of gatorade go in after a couple of pees and relax. Do an afternoon appointment if you are getting stronger negative results with that. Eat a good steak dinner or a nice juicy burger tonight. Its nerve wracking but you sound OK to me. Let us know the results...