I am writing an opera.  While I am not hiding any orchestral instruments, I am optimizing the voices to only show the vocalists singing at the moment. Consequently I have a different number of staves for each page. This means that before running the vertical collision remover there is no way to adjust the space between staves to exactly fill out the system to the page margins, by setting the space between staves to be the same.  Ideally this would be an option with the vertical collision remover to expand the system exactly to the page margins.  I am currently manually adjusting the space between the staves on each and every page so that the bottom margin is also the bottom of the system before running the Vertical collision remover.  At about 400 pages, each time I need to change the layout, of exactly which measures are on which page, and yes I do lock my systems, then the optimization changes and each of the 400 pages has to be manually corrected before re-running the Vertical Collision Remover. There has to be a better way!