yeah they run a 20mm small end. They're floating though.
I don't know that you'd need the extra strength that the twin cam CA18's offer D. Like I say, till I weighed them, I didn't even spot that they were different. Given that extra weight will take more energy to speed up, you dont really want too much extra weight if you can get away with it.

I weighed CA18DE, and DET rods, and they are the same part.

It appears I dont have the weight for the CA18de/det in my book, but I found the following weights,
A15 rod with cap and rod bolts; 516.6 grams.
CA16DE rod with cap, rod bolts and small end bush; 651 grams

I must have forgotten to write down the CA18 rod weight, but I'll do that if I remember this week some times.