I don’t really see an issue with the screen shots – where specifically do you feel that there is “a lot of space around the main box” ???
Above the first title is around 3 cm white space. And at the bottom same when it’s a large order and there are a lot of products I quickly need a second page because the paper is not used to the end). and same left and right too, thats even acceptable but above and at the bottom is really taking so much space.