Re: Beginner question about leaders/tippets
The "x" designation was designed to denote diameter. The thought is that diameter is more important than break strength. Smaller diameter tippets are used for smaller flies. Larger diameter tippets are used for larger flies. The confusing part that break strengths and diameters are not consistent between brands and in some cases within brands.
As a warm species fisherman, don't overthink the topic. The reality is that your fish are not leader shy. Taper your leaders to the lengths and tippet sizes that you think will work best for you.