I think you should just map to the intensity of the song, and if the intensity doesn't allow for a map that's harder than a 4.21 star song, there's no point in overdoing it, it will just end up being an over-mapped mess.
However, if you feel like the song allows for a more intense map, yet you don't know how to make your map fit that intensity, I can definitely see your point. Sadly I can't help you though.
It all starts with choosing a high slider velocity val0108 style (if you do like 120-160 bpm choose something like 2.8-3.2x, 1.4-1.6x for 240-320 bpm since it works as a multiple of bpm).
If the song is more of the 120-160bpm feel than the 240-320bpm feel then you are going to want to use more normal streams with stream jumps or hanzer streams to emphasize the different sounds instead of going all out with the spaced streams like val/saten tend to do. Personally I think val pulls off the "double bpm" style better than saten tbh.
Note how Hanzer manages to accomplish mapping 2 different sounds throughout the more intense sections of the map by using small spacing to represent one sound broken up by larger spacing to represent the more intense but less frequent sounds (ie. a lot of the streams do this).