My greatest concern with a home demo is perception. You obviously really like these speakers and I submit that they would have to sound pretty bad in your space for you to return them. As many have stated above, pick up late Saturday and return early Tuesday is not enough time to make a fair (to you) judgement. I would hope that the audition be at least a week.
Lest we forget that old beast confirmation bias!
Warm Regards,
barts