Going against the current trend to shorter paddles, I prefer 220 to 226 depending on blade size. The main reason for this preference is my preference for a low stroke. My current favorites are a 226 AT Xception and 220 Werner Kalliste, both with bent shafts.
I studied Doug VanDoren’s video on a very low Greenland stroke with elbows near the body and emulate this with the paddles mentioned. This combo of low stroke, moderate size blade and longer length is very efficient for touring. It is easy on shoulders as well. I especially like this combo out in windy conditions on the open ocean because it enhances relaxation and bracing.
If you paddle a kayak which does not
waggle much, then a low-angle paddling style is very efficient. With my extreme torso length (long even for 6’ 5"), I have a Werner Camano 240 for low-angle work, but right now I don’t have the long touring kayak that would go with it.
Hmmm
when I got my Werner Kauai (220) a few years ago, it was touted as a high angle paddle. The 230’s were more conventional lower angle paddles. Times they do change.
220?
I guess I don’t consider a 220 paddle particularly long - 230 maybe and 240 definately, but not a 220. Hey, whatever works… 
Efficient
When you say;
“This combo of low stroke, moderate size blade and longer length is very efficient for touring.”
What is this statement based on. I have heard it before, but always from someone behind me. My definintion of efficiency is the most amount of propulsion for the least amount of effort. Just curious.
Falcon