Are you ready?

I would better prefer more space on the left of the model... thus

composition is not the best.

First time I used light boxes, thanks for your oppinion.

Depends on what you are trying to achieve. The lighting on the model herself is not bad.

Main question: what do you want to do with the background? How visible do you want it to be? Do you want it to be visible and IN focus, or visible and OUT of focus?

The answers to these questions will dictate some technical decisions that will affect your lighting choices.