Kaidoh is a Stamina freak since the beginning of the series and the one that has trained it most. His whole game is based in that amazing stamina.
As I said before about Ryoma's case: "Maybe Atobe's stats were taken right now, at the camp. So, he might got a way better stamina compared to national's Atobe. Also, Irie has 2 on Stamina even though he played some really long tie-breakers. Tezuka has 3 in Stamina yet he never sweats in long matches lol. 3,5 seems still fine. At first I really didn't want to do Echizen, he's the protagonist and in some moments kinda gets 7 in everything... So I think the stats I made from him are fine, but they aren't accurate at all (he's unpredictable and data doesn't work against him, just like against Fuji and Tezuka,).
Also, I don't want to change any of the Data given (Tezuka, Atobe, Irie, etc...) just because we're using those as a base."
As Airgrimes said: " due to Irie having an extremely high Mental, I expect it allows him to cope with the long match mentally. Exerting energy when necessary."
I expect the same with Echizen. He hasn't the highest Mental, but it's already above Atobe's.
If you agree with the rest of the stats, I'll do some other stats... I might change Ryoma's stamina in the future.