5-B metal, but yeah, neat stuff
I thought it was the opposite? Max Power Roshi could have killed Oozaru Goku with the kamehameha (Yamcha sure thought so, although I don't know if he had Ki sensing at this time) but decided to blow up the moon, so he doesn't, ya know, kill Goku. Although, if that's the case,
we kinda have to downscale 21st Budokai Goku to High 6-A via Oozaru downscaling and yada yada,
BoZ Oozaru Goku only had a PL of 100, so he'd be weaker than everyone (We have a PL on) from the 22nd Budokai, so don't think we can give 5-C from that,
Master Shen is pretty blatantly above Yamcha's level, since it's only when Roshi buffed up did Tien say that Roshi was even stronger than Shen
Shen was also seconds away from killing Chiaotzu, so him being anything below 5-C doensn't really work
(Btw I tried looking for anything that compared Tao to Shen but I found nothing)