I want to ask: Will you wake at 6:00 tomorrow?
"明天你都六点起床不起床？" is not a valid sentence in Chinese.
If we remove 都, and make it "明天你六点起床不起床？", it is valid but a little awkward. Because we usually don't say things like "起床不起床?", "吃饭不吃饭?", "睡觉不睡觉?", "学习不学习?" etc. when asking questions. The point here is that we normally don't repeat the whole word before and after 不 in questions, instead we simplify it.
Note: It is ok to repeat the whole word before and after 不 in declarative statements, like 老师喜欢不喜欢你，我真的觉得不是什么问题. While it can also been simpified as 老师喜不喜欢你，我真的觉得不是什么问题.
Here is the natual way to say it in Chinese:
起床不? or 起不起床?
吃饭不? or 吃不吃饭不?
睡觉不? or 睡不睡觉?
学习不? or 学不学习?
Back to your question, "明天你都六点起床不起床？" is not correct.
If you are asking a person of his/her get-up time in the moring, you would say:
你早上6点起床嘛? or 你早上6点起来嘛?
If the listener usually gets up at 7 o'clock, and you want to know if that person plans to get up at 6 o'clock tommorow morning, then you can say:
明早你六点起床不? or 你明天早上六点起来吗?