Are you using the right length paddle?

For the last weekend I have been out with Jan just paddling with the old Necky Kyook I got from Craig last year.   She has been really on my case about correct form, and paddle placement.  SHe is of the opinion that my paddle (a 230 cm bending branches) is too short.  SO I did some searching and came across this from Bending Branches:

http://bendingbranches.com/paddles/kayak/fishing/angler-pro

Notice your height and the width of the boat come into play.  My 230 is most likely too short, and I should be using a longer paddle. 
Which will be bad news for Jan as her lessons on paddle stroke have now left me to paddle fairly well, and get decent enough speed in a SIK for to not be able to stay with me.  No word yet on how that will effect the "Das Barge."

 Like most of us, I only have one paddle and have rarely ventured out for another.  Time to start looking.  Unless of course I can talk Jan into a Stealth 575, than I can keep the paddle I already have . I can see it now, if Spend $2900 for a 575 I save $120 on the paddle!  What a deal right?   Didn't think so either.

Back in my paddling days I used a 240cm Werner Camano. I'm 5'10 or 5'11 depending on the day. 
I think not only height comes into play.
Boat width (and now seat height), paddle stroke, and physical capability also need to be considered.
Like a kayak, try before you buy.
Bottom line, what's going to get you were you need to be with the least amount of effort that won't kill you by the end of the day?
Which should come first; comfort or efficiency? It's really all dependent on the user.

What's the best way to demo a paddle to fit with your kayak?

What's the best way to demo a paddle to fit with your kayak?

Any group gathering. Just ask to switch with people with different paddle lengths.
Berryessa was a great place for that.

Paddle length is very subjective. I have a pretty steep stroke so long paddles trip me up. The shape of the blade is also important as we'll, depending on whether your stroke is shallow or steep.

I was using something way too short until I got my new Aquabound Manta Ray. I didn't know how much I was twisting around and leaning down to get the blade completely submerged until I got the 240. I don't have the old one (Crack of Dawn Tsunami), but I suspect it  was something like 220 or 210.

I took my GF out for her first paddle in a couple years in the Redwood City marina yesterday afternoon, and I was very happy that I brought along a buddy's spare in my kayak. (thanks for the loaner fuzz!) The paddle that came with our long-neglected cheapie Pelican is WAY too short, maybe 200, 210. Putting his 240 in her hands made a HUGE difference!