HU Cash Games -- Raise Amount for Deeper Stacks?

[Kwantum]

I've been playing more and more HU cash games, and I've been wondering what an optimal raise size is once you get deeper.

Let's say that you and your opponent are 200 or 300 BB deep -- what do you think a good standard raise size should be? Typically, I just mash the pot button when starting at 100 BB stacks (3x raise).

I suppose the idea would be to make it a bigger mistake for your opponent to 3-bet you too lightly and also force him to put in a little more money while he'll be defending OOP.

Thoughts?