If we use the Frazier fight as a blueprint, you'd have to favor Ruiz. He wasn't quite as fast or mobile as a prime Frazier but in terms of styles and physical tools Ruiz had some things in common. Mathis always struggled with aggressive guys with quick hands (Quarry beat the mess out of him too). I think the fight would basically start with Ruiz struggling with Mathis footwork early before slowly breaking him down with his fast combinations. Ruiz did have trouble with Parker who has good lateral movement and couldn't convince the judges to give him the nod so I guess it boils down to if A) Mathis can maintain his preferred range and B) Ruiz can put together more than 1 punch at a time and slow him down. Mathis does have the tools to pull off a win but I wouldn't hold my breath.
Not sure about it, he is probably average height maybe a bit taller I don't pay attention to the tape all that often I just look in the ring. but when glaringly obvious things like Joe being 6ft2 pop up just HOW?