Less style in variables.less

Hi
I've followed the instructions in documentation for using less files in the template
I've setup correctly.
I notice something changes. I mean, header height in style.less is not the same as style.less

But: my main question

I change a variable in variables.less and I can see the change

Now, to put all changes permanently and go back use the css files, should I download Koala, or something similar and compile the less files again?

Anything else to have in consideration ?

Thanks

Solved with Koala

Installed Koala, added "canvas" folder, edited variables.less and complie style.less
It generated the css file and all going fine

Thanks