I have built a Canterbury J from the hull and parts supplied by a club member in New Zealand.
Today was the first trial sail and she sailed just beautifully. Very responsive to rudder, but controllable with 65% exponential which sort of makes up for my big thumbs. The winch is an RMG with a self tensioning drum operating in a continuous loop below the deck. Power is from a 2S1700 LiPo battery which saved me over 220 gm. of unneeded weight compared to a NiMh or NiCd battery. The overall weight came in at 6.6 kg., 6.5 kg. is the class minimum.
Attached are a couple of photos. I have lots more starting from the day I unpacked the big box. If anyone is really interested I can post them as well as how she all went together.
One thing I noticed in today's test was that the J accelerated very quickly and seemed very fast even with the light winds. This is only my second sailboat and I haven't had any opportunity to see other class boats sailing, so you experts may consider this normal.
Building the "kit" was not overly difficult but took me quite a while, I'm not a fast builder by any stretch.
Ian