Yes, you can fine-tune the collision by adding my magic-shader (in my little tutorial) into your model, only surfaces that have this shaders will be physical.
Depending on the model form, it is sometime better to manually re-clip model in Radiant with brushes (if you need something rather basic), or sometime you can use my special shader if you want something smoother that could be hard to do with brushes.
Take in mind that "weapon_clip" stop all shoot (and players too), while my shader "wood_clip" act just like a wood texture: bullet can pass through
(dealing less damage).
By the way you can use my shader in both situation (directly part of the model, or added in radiant like a standard brushes).
The path is textures/joekari_q3map/wood_clip, unfortunately, the editor image is not present in the smokin'guns package (so in Radiant, you will have a "shader image missing" texture), but it still work.
Well, I'm the only one defender of ambient light in the team
If you are curious, compile your map removing "_minlight" key, and adding instead a "_ambient" key in the worldspawn, "8" is a good value.
What's the difference ? Minlight ensure the amount of light is at least equal to a value, if not it fix it to that value. Ambient add a constant value to the amount of light everywhere regardless of the initial amount.
Minlight create flat (leveled) light where there isn't enough light. Ambient does not. Changing ambient's value affect the whole map (that's why many mapper don't like it), while changing minlight's value affect only place where there is not enough light.
About size of the money (and other) pickup:
That's a little annoying, but keep in mind that the bounding box of item are larger because it's more easy for player to grab them. Have you noticed that you get money without touching it ? I agree this is boring in many case, maybe one day I will change one or two things in the game code...
@ Pardner: it is useless to change the entity definition, q3map2 doesn't care about that. I just think the game doesn't want to spawn entity that are inside (or intersecting) map geometry.