Big Question: Creating High Res or HD sprites what is the proper size in Mugen?

[ShotokanTuning]

I was wondering what is the right size for High Resolution (HR) and Full High Definition (Full HD) sprites in Mugen?

Like for example for we have many different type of games and simply creating a high res version that is 2* the size isn't always that handy when matching sprites with each other. With HD this becomes even more evident.

I'd really like if someone posted proper size and scaling factors for SFA, CvS, SFIII, Guilty Gear XX, Blaz Blue, KoFXIII, MotW and Samurai Showdown VI.

Now this could be interesting, what do you guys suggest is a proper cm to pixel ratio? in default resolution, HR and HD resolution? I know this varies by game series but sort of common default could be established if we think it through.

Like let's say we have a guy that is 180 cm high his stance is around 175. How many pixels should his height be in default resolution, how many in HR and how many in HD?

I think something like this could be useful in a Mugen FAQ for spriters.

Thanks for helping me out,
ST