Given his attitude, he was clearly a skilled player and I bet he was one of the best of his Age Group, so he was probably Nationals! Tezuka level when he faced Byoudin, but Byo was just stronger than that.
IMO, The only Players who would've been accepted into the camp during the G10's Middle school years would be Byo, Tokugawa, Oni, Shuuji, possibly Mouri and maybe Irie if they could get his data. And Duke if he was Japanese. I don't think Ochi would because lacking his trademark height, Tohno because he probably wasn't as good as his executions (given PoT tradition, he has to have evolved a consifderable number of times to get 13 moves), Kijima wasn't famous enough to make real good negotiations, Ryuuji likely couldn't use Nitoryu to the point where his partner was like "Ryuuji you got this, Imma take a nap", and I don't know enough about Kaji.
---------- Post added at 12:35 AM ---------- Previous post was at 12:31 AM ----------
Given the g10 I have created a comparison list of Ryoma Generation Players That I think they'd have been equivalent too. Feel free to discuss as that makes it more fun.
Byoudin= Yukimura
Shuuji= Shiraishi
Duke= Sanada
Irie= Tezuka if Serious, Marui if not
Oni= Tezuka
Ryuuji= Kaido
Kijima= Oshitari Y.
Tohno= Kirihara (Non-Devil)
Ochi= Oshitari Y.
Mouri= Renji
Tokugawa= Sanada