I went through a serious stage of obsessing about every tea factor. If you are at all like me, though, that process is for your benefit only. In other words, it isn't so much the amounts you use as it is the consistency with which you do it. The consistency helps you learn how to brew tea. If you brew 6oz of water with 6g of leaves every time then you will get a sense for what that is like. If you use 6.2 oz. of water with 6g of leaves every time, then you will get a sense of what that is like. Eventually, you may decide that 6.2oz tastes better than
6oz, or that 5g of leaves is all you need to make a good cup of tea instead of 7g. At some point, you will likely become familiar with what it takes to brew a good cup of tea without using precise measuring devices.
Having said that, I use a very small (less than 6oz) yixing pot and put as much water as it will let me. I do weigh out the amount of leaves I use, but don't time my brewings much anymore. When I brew the first brew, I get slightly more tea than when I brew my fifth brew, because there is less room for water once the leaves expand. So the amount of water I use changes as I brew and there is nothing I can do about it due to the size limitations of my pot. I personally feel that using too much water is worse than using too little because I'm not so crazy about weak tea.
And if you are using a scale to weigh your tea, you will likely be mocked. I know I am, though I enjoy that as part of my tea routine in the morning (not the mocking, the tea weighing).
cha bing