I'm not really sure how to approach that by myself (idk if scaling would work, or maybe even a little model tweak)

Because right now, they are all bombs are the same size
I think that the storm and skater bomb, should be bigger than the minute bomb (like 1.2 times or so), and (or at least) the detonator, should be bigger than all of them. (like 1.5 or 2 times the minute bomb)
I noticed that there was something off, since I am working on the patchouli books, and their entry says, that a detonator is a big variant of the minute bomb

Tried to find some videos (with time stamps) to show of their sizes:

• Minute Bomb
• Skater Bomb
• Detonator (With Good comparison to a minute Bomb)

Got some Images (Roxas for scale)

• Minute Bomb:
  
  

• Skater Bomb
  

• Storm Bomb
  
  

• Detonator (with Minute Bomb)
  

Minute Bomb: Player Size or bit smaller
Skater & Storm Bomb: 1.5 times player / 2x times minute bomb
Detonator: about 2x size as player

I think that also the spawn rates might need to be adjusted, with the other bombs being rarer, since having always such a big bomb could be fatal (probably would fit well with the high/low rank nobodies too)