ImNotFree

Unpaids right, Baki is 168cm or 5'6 making him short and surprisingly Hanayama is only 190.5cm or 6'3. Really only Jack Hanma(213cm or 7'0) and Pickle(245cm or 8'0) are all that tall.

When he goes to these world, you could have him hold back his strength to the point of matching his opponents if they interests him like let say Hayato(from History Strongest disciple Kenichi) and fighting them using there own martial arts to perfect his technique of there martial arts, or if they are annoying person(like Issei for example) he can just toy with them as such fights are fun if they aren't over done.

Him

For the first time this story got a real laugh out of me.

Not to suprising. He already got kai-oh-ken.

I personally think those that eat a devil fruit would no what it is but in Luffy's case he is an air head who didn't know he had a dad until Garp told him so when he ate the devil fruit making him stretch and Shanks told him he ate the Gum-Gum no Mi he believed it. Though this my personal idea on how Luffy always thought that he had the Gum-Gum no Mi which is probably wrong.