I have tried SDKHook_Touch, yes. I got CollisionHook working, but it is exactly the same as using SDKHook in this case. The model is custom and it does support physics. I have also tried prop_physics (and override) but its the same.
If you want to check out the model, here it is: https://files.catbox.moe/rx61p6.zip
Here are some pics too.
And here is an example, if I shoot through the corners, it still registers as getting hit. Its like its using the bbox instead of vphysics.