Working with underwater material

Hi everyone,

I’m working with some underwater footage for a scene on a film, and both cameramen who provided the material mentioned that it’s worth slowing down the footage beforehand to make it look smoother.

The first one suggested slowing it down to around 80–90% of the original speed, while the second recommended converting the 60 fps footage to 25 fps.

What would be the best approach? I’m editing in 25 fps and the footage is in 60 fps. Should I just drop it onto the 25 fps timeline, or should I interpret the footage as 25 fps, or is there a better approach? 

Thanks