Multi-Server Setup/Mapvote Questions

I recently set up a gmod server installation on an Ubuntu 15.04 box. By following the guides I finally figured out how to use the Steam Collections to download a gamemode/maps/addons and start the server with them. My question however, is how do I have multiple servers setup to share a single download of all of the cs/tf2/etc assets so that I dont have multiple servers with wasted space. I am limited on my space as it is a VPS. I currently have one server downloaded and I was able to successfully launch a ttt and murder server off of one installation just with different startup scripts with ports and collections. If I do this will one server overwrite the settings of another or cause problems?

Also, when I use the workshop collection it launches the gamemode successfully but I dont see the gamemode folder nor the map files anywhere on the server, not even in the normal gamemode folder.

I have also been trying to setup thismapvote addon by adding it to my collection but it does not work with ttt even after following the instructions. What am I doing wrong or is there a better mapvote plugin out there?

Also, since I am relatively new to gmod server hosting, what are some of the must-have addons for adminstration, improvements for gameplay, votekicking, etc?