I'd like for, narrative wise, the 22nd Budokai increase to be bigger than the one he had at Karin. He received a very big increase Vs Karin, indeed. He couldn't do anything to Tao before and outclassed him later. Roshi thought he likely couldn't defeat Mummy if it were Goku from the 21st, but he one-shotted Mummy.
But in the 22nd Budokai... Roshi thought Goku was in a stiff match from the start, Vs Chappa, and Goku easily dominated him without any effort at all. Then, Vs Kuririn, Goku decided to use more effort and totally outsped and outclassed Kuririn, and Roshi was all surprised. And then, he decided to go more seriously when Kuririn used cheap shots and disappeared from everyone's sight except Ten's. Roshi admitted upon saying that, that Goku was likely stronger than him... Saying Goku only gets better and better. And then, Roshi anticipated Goku Vs Ten as the match Kuririn couldn't hope to see other one like that and to pay close attention... And still, as Roshi didn't even know, Goku was holding back a whole new level of power, his battle level, that he used unrestricted when he knew he wouldn't kill the opponent. Those are big layers separating Karin Goku, who Roshi thought was already in a stiff match Vs Chappa, to the Goku who used battle level Vs Tenshinhan. Not only that, but those were 3 years of heavy training with the intensity already surprising Roshi when Goku took so serious the thing about not using Kintoun as he came swimming from a different continent and didn't seem even tired. 3 years of this intense training with all the reactions shown should triumph Karin's training, which were 3 days, but yeah, wielded exceptional gains too, but the level of effort, intensity and all the big surprises Goku kept giving them at the 22nd seems more impressive imo.
It's also worth noting that Goku and Tenshinhan seem considerably above Roshi, while it seemed to be common knowledge before Roshi was only slightly below them. Roshi stated he'd likely lose to Tenshinhan and that Goku likely surpassed him... But that was before seeing both Goku and Tenshinhan upping a level of effort in the final match. Tenshinhan used more power when he caught Goku's super speed and Roshi was surprised at Ten's finger speed calling it a machine gun... And then Goku stated he could finally dish out his battle level, which Roshi was surprised to hear. So Roshi admitted inferiority to a Goku whom he didn't even know had another new level prepared.
Goku (battle level) > Tenshinhan >> Goku (full match level) ~ Tenshinhan (initially in the match) >= Roshi
I'd say Roshi is like 75% ~ 80% of both finalists.
