As a side-note and recommendation, I would think small where external runtimes are concerned.  Too many individuals get caught up in creating runtime upon runtime of content and completely lose sight of what they have.  Install content that you will be certain to use most, if not all, the time.  That would include models, morphs and basic textures.  Then think about the type of project you would like to develop.  Gather your textures, props and clothing, dump them into a special project runtime, create your art, and then delete the folder.  You eliminate HD clutter, save precious HD space (I don't care how large your HD is, it is never enough to hold Poser content), plus you know what you have.

Make it easy for yourself.  You will realize soon enough how quickly you can get buried literally in your art.