Shadow on bottom part of last score page

Reduce the scaling in Format>Page Settings.

A stave space of 1mm seems to work and that is about the minimum suggested by Elain Gould in Behind Bars. You may be able to use something slightly larger in the score if you decrease the size of the top and bottom margins. Of course, the individual parts would use a larger size. The MD doesn't have to read individual notes at pace and can peer closely if it is necessary to check something in detail.

I also note that you have been inconsistent with the placing of chord symbols. In the guitar part for example, some are above the stave and some below. That is likely to take up more space than if they were all on one side (top is normal I think).

Oner more thing, you can save some space by moving things like dynamics horizontally to avoid collisions with things in adjacent staves. It's a bit tedious but sometimes is the only way if you have high notes on one stave and a dynamic on a low note in the stave immediately above.