6'4 360 lbs, how much water should I be drinking

As much as you are thirsty for?

http://www.snopes.com/medical/myths/8glasses.asp

Drink when you're thirsty, have a glass before meals to help you feel full a little faster, drink more if you're sweating a lot.

When you're properly hydrated, your urine should be a very pale yellow: https://health.clevelandclinic.org/2013/10/what-the-color-of-your-urine-says-about-you-infographic/

Yeah, I would think based on that alone you might want to up your intake. I go ALL the time. LOL

Half your body weight in ounces is a pretty good starting point. Adjust as you feel necessary.

The interesting thing I've discovered about water during this year-long experience came to me just in December.
I had learned how to make Neapolitan-style pizza dough and was having a 450-calorie thin crust pizza for dinner on alternate days. That was a 1700+ gram sodium blast late in the day. For several weeks I had observed my weight increase by 1 lb each day following a pizza, only to fall 1.4 lb on subsequent days. Clearly, my pizza was causing water retention. One day I finished my pizza, and then drank 40 oz of water before going to bed.
That was a mistake, as I didn't sleep well for having to get up and piss. However, the next morning, I measured a weight loss. For my next pizza, I followed it by drinking 32 oz water before bed, slept well, and again measured a loss. For each pizza since then, I follow it by drinking 32 oz water before bed, sleep well, and have measured a loss the following day. The thing about water and salt is that you need water to maintain salt in solution inside your body. If you have too much salt, your body holds on to all available water. If you give your body more water than it needs to handle the salt you already gave it, your body will quickly get rid of the excess of salt and the excess of water. On recent non-pizza days I was having leftover Christmas ham, which was an even bigger sodium blast. On those days as well, I made sure to drink an extra 32 oz of water after my evening meal.

During my Christmas vacation, I ate too much of everything and packed on extra weight. From January 2, I've been back on my regular food plan, compensating for high sodium with more water, and have lost 9.8 lb of my vacation gains.

Experiment and see what feels good to you. I used to try for 1/2 of my body weight (in ounces), which was a general rule that I had read, but that's not enough for me (BW = 140, so this would mean 70 ounces).

I feel good at 120 ounces. My skin is not itchy and dry like it was for YEARS and I hardly every get congested.

Sounds like a lot, but it's 5 water bottles a day (at 24 oz). One in the morning, one for lunch, one in the afternoon, one for my workout, and one after. I'm in a rhythm at this point and don't even think about it anymore.