Skip,
Have you had a chance to fly it yet ? Just curious as to your impression.
Tom Stennis flew his Sid Austin ARC version Curare on 5S with an E Flite Power 60. He said it flew well, but he wanted more vertical grunt. He switched to an AXI 4120/14, and said he is happy on 5S. He is also (like you) very light .... about 6 3/4 lbs.
I'm waiting on my own Sid Austin ARC Curare, but I'm going 6S like you. I'll be going with trike gear .... hope to be about 7.0 lbs.
Ed