With regards to skill, Shin is a combat prodigy and has victories against people with literal decades of experience on him under his belt (Rinko, Gai Mou, Houken). He's not at the level of actively trolling people in combat as you described with the Merlin and certainly has to work harder for his wins, mostly because he's usually the underdog.
I feel it's like 8/10 in favour of Benedict. Seem fair? Shin might get a lucky shot here and there and he does have a tremendous ability to keep going. There's actually a scene that's softly played for laughs where Kyoukai cuts Shin on the arm in a spar and he flexes the wound closed. Not sure if that's viable for a feat but, given how he both of his thighs pretty much laid open by Rinko in their duel, killed Rinko and then rode up a small mountain and confronted Renpa, slashing damage is more of a suggestion than a viable strategy to keep him down.
Benedict should be able to outskill him fairly consistently so he takes the majority.