At bare minimum, far above the Galu who beat him, likely at least rivalling his full tournament level. At most, fairly above 22nd TB Goku/Tenshinhan in general. I'd go more with the former since along with saying whether or not he saw the 22nd TB's entirety has no evidence either way, it'd be quite absurd if he didn't expect a fully developed adult Goku who'd had 3 years more training to not be leagues above the one who oneshotted him prior and still believe things would go differently if not at least above this plateau.