Dusty-
another vote for neither. Big fan of Thiel speakers here. Most models need room to breathe (no pun). A smaller model like the 1.6 will do well in a small space, while, a larger model (more drivers) like the 3.6 will do better in a larger space. If you feel the 1.6 is a little lean in the Bass, you could always add a small subwoofer (REL or Sunfire).
Keep me posted & Happy Listening!
Sidenote: I just scored a sweet pair of CS 2.4SE and my space is 16x12x14 (w/d/h).