This is a bit tricky, and I'm aware that Macinstaller is currently a bit poor with multiple Posers. It only accepts one Poser at a time and needs to restart after you select "Change Poser". This will be improved (hopefully) soon by allowing you to switch Poser "on the fly". I was working on it for a long time (the idea is as old as Maconverter when I tried to look for a better Texture fix than just removing), and the 4.0.2 betas arrived when it was already designed. So it is just not prepared to handle multiple Runtimes, and I suppose that 4.0.2 becomes final (and makes 4.0/4.0.1 obsolete) before I could finish this major change. For your custom installations there is a good solution: Choose "Source Folder" as Destination for both Libraries and Geometries, and "Source" for Textures in the main popup as default. This way you can keep just one copy of each file where it is (anywhere on your disk(s), you can even split it up on various places), and only minimal data will be copied to the Runtimes. You can turn off "4.0/4.0.1 compatibility" if you have separate folders for 4.0 and 4.0.2 and save some more space. The only disadvantage will be the need to install everything 2-3 times (with the annoying Poser change in between), but (once again) Macinstaller was designed to address only one Poser at a time, with an easy handling of upgrading/re-installing one Poser, not multiple ones at the same time.