Remove space between column headers and data in tablix - paginated report

Hi all, 

I am creating a tablix in a paginated report and am having an issue removing the margin between the column header and the actual tabular data. I essentially want to decrease the red space in this report.

In the editor I have tried simply dragging my cursor along the column header rows to decrease the size, but that does not fix the issue. I have also tried making the bottom padding equal to 0pt and setting the SpaceAfter variable equal to 0. In the second image you can see I scrunched up the headers to the second table and set the alignment variables to no avail. Any ideas?

Appreciate your help!