It was impressive, but it wasn't a clean 1v1, and Tou had to keep his head on a swivel and command the army. Ka Rin had Kou Yoku essentially harass him to keep his attention divided.
Your guess is as good as mine, but my perception is quite different.
I don't think he would've been easy work by any means, but Rin Ko was a monster. Ou Hon wielded a spear and struggled to keep up with his speed, and Shin was amazed at his physical strength. Combined, they had 5 attempts on Rin Ko's life.
Ultimately, I think if Rin Ko kept a tighter guard and didn't lose some fingers and/or wasn't written to have injured his shoulder, that fight goes differently. He really was like a tiny Hou Ken imo.
Kou Yoku did well against Tou, but Rin Ko was the mfer that broke through Ou Ki's lines and drew blood. Though Kai Shi Bou's strength was compared to Ren Pa's and Kyou En fought their lord + 4/6 6GGs (and some multiple times), Rin Ko was considered the most dangerous of the 4HK by many. I don't think CW Kou Yoku measured up that.