I don't think it's a real big consideration Alan.
If the speaker had a real low impedance drop in the upper frequencies (like some ML's) and
if your speaker/amplifier distances were very long (let's say >25 feet but then I'd have argued that monoblocks made more sense) then I'd suggest you search out a lower inductance speaker cable. None of those scenarios applies here. So certainly a 12 gauge, give or take, will do the job without any sonic degradation.
I did run across the following link:
http://members.ispwest.com/edgrochowski/article1.htm where someone was mucking around with their 1.6's that you might find of interest.
Your greatest challenges I think are going to have to do with speaker placement and investigating some rear room treatments. Nice speakers btw.
