Disregard the title of the topic for a second. All I'm looking for is a deadlift weight that will create the kind of back support I need for squatting 455. If it's ~300, fine. If it's ~400, that means I'd need to work on it a little. I'm not looking for a ratio; what I said was a guide for me when I started. I didn't use it by making sure that my deadlift was exactly twice the weight of my bench. I merely made sure that my squat was higher than my bench, and my deadlift higher than my squat.
Obviously, now that I have some clearer goals, this doesn't matter as much. And while it may make sense to a bodybuilder or a strongman to make any extra possible gains, this would really be a waste of time for me. I'm looking to attain certain maxes, change into a maintenance lifting schedule afterwards, and spend that extra hour a day I'd spend lifting for something useful, like combat training or getting my pilot's license. It's all about efficiency and packing on strength I'll never use is really the last thing I need.
If someone can give me an estimated number for the deadlift, that would be really helpful. Otherwise, you're not really being beneficial.