Help required to switch models in Sonic Adventure 2 PC

[The drunkard from space!]

I'm sorry if this isn't the best place to ask a question like this, and sorry again if this topic isn't suitable for discussion. I just wanted to ask how one could go about switching models around in Sonic Adventure 2 PC. I have SA Tools but I don't know where to start. The Sonic Retro forums don't do a good job explaining how to switch models. Could somebody help me please?

EDIT: What would be really useful is just knowing what the model files in the SA2 PC are even called.

EDIT: Okay so I think the main models I'm looking for are these in the folders resource/gd_PC (although I could be completely wrong):
sonicmdl.prs

sshadowmdl.prs

ssonicmdl.prs

teriosmdl.prs

ticalmdl.prs

amymdl.prs

chaos0mdl.prs

knuckmdl.prs

metalsonicmdl.prs

milesmdl.prs

rougemdl.prs

I've tried simply renaming them (for example renaming sonicmdl.prs with chaos0mdl.prs) but that only seems to crash the game.

Edited August 25, 2015 by Kool Kirb

[Yoko/葉子]

This has given me weird ideas of replacing Egg Golem's face with Alex Louis Armstrong's.

[Monkey Destruction Switch]

I really am not knowledgeable about the subject at all, but I have a suspicion that the game probably doesn't work in such a way as to allow you to just "switch around" models. The different models are programmed to do different things, so you likely can't just simply assign a model to a different purpose. If you want to have different characters doing different things, you would probably have to actually edit the model of a character into looking like a different character.

Disappointing, isn't it? I know I'd love to just mix things around willy-nilly.

[The drunkard from space!]

People on Sonic Retro have already replaced Sonic's model with Tikal and Rouge's with Metal Sonic, so I already know it's possible. Retro just doesn't do a good job explaining how. I'd join and ask but I've already tried that previously on another subject and they all ignored me, I have a feeling that'd happen again.