I feel that pre-shave and shaving techniques are the key factors in a baby smooth butt shave.
Today, I teased out Gillette 7 o'clock Green Russian after using Feather Hi-stainless for quite sometime, the Feather had less resistance compared to 7 o'clock but the quality of the shave is pretty much the same.
I apply Proraso pre-shave cream on my face before shave,
Razor use - Weber DLC head with BRW bulldog handle
Brush - Omega Hi-brush syn brush
Soap - MWF
Aftershave splash - FA sports
You get your pre-shave prep & techniques right, blades isn't much big difference.