First off looking at your horse it looks like he would be a good candidate for the wintecs, he appears to not have much wither and a fairly flat back. Secondly I have found that wintecs fit kind of small. I normally ride in a 17 inch but had to go up to a 17.5 and likely should have gone up to a 18 inch, but maybe thats just me.
For the CAIR, there are lots of people on either side of the fence, some people love it and some people hate it. I am indifferent, I see no difference in my horse's back with CAIR vs. normal flocking. Some people claim that the CAIR make for a bouncier ride, I personally like it because my horse has a very very smooth trot so I have to really work to post and the CAIR kind of helps me out there :p
RH Queen O Anywhere "Sydney"
2009 Sugarbush draft