2 Questions here...

Okay, here I go:

1)How can I change the unit portrait model?

2)How can I change the model size? Do I absolutely need Wc3 ArtTools?

Thanks guys!

1)How can I change the unit portrait model?
In WE open the "Object Editor" and under the "Units" tab find your unit.
Next look for "Art - Icon - Game Interface" and change it to whatever you want.

2)How can I change the model size? Do I absolutely need Wc3 ArtTools?
Almost the same as the top one but look for "Art - Scaling Value" and change it to whatever.

Hope this helps you.

Thanks man! I'm new to World Editor and when you start there's so much things!

Even when you've been mapping for nearly 2 years, there's a ton of things to learn.