How big do you think this gap is? Tenshinhan definitely had a slight edge but Yamcha was able to hold his own. Did Tenshinhan power up when Yamcha used WFF 2.0?
Tenshithands acknowledged Yamcha's strength and the way their fight went, it showed less of an advantage than Vegeta vs. Kaioken Galu. Don't think the gap was that much. Kuririn also thought Jackie would beat Ten after the fight.
They were about even at first in H2H, but when the fight got more intense it became evident that Tien was much more competent at defending and applying countermeasures, especially in the anime version.