I read Pete's thread on pruning, which was very interesting.

I have two CDDN's from Harvey which are doing well.  However, the first one to grow has slowed down and was surpassed by the second.  I suspect it is because of two branches.  Should I prune the smaller branch to improve growth on the main trunk?

I have some terrible quality night shots to make my point :)

 

Hi,
Hard to understand exactly the situation of that tree.
I just got it, the big branch on the right belongs to the pot behind...

Here after is just my opinion, the tree is yours, and you'll do as you like , of course :
I would keep the tree with two branches.

You have some options:
Option1:
Pinch both shoots now, setting them at the same height.
Could it be that the left shoot is getting more sun ? If so, flip the pot, putting left shoot at right shoot's place.
Could it be that the whole pot is not getting enough sun ?

Option2: Next Spring, before bud break, shorten them both at 2'/50 cm and let them grow from there.
Of course, you won't have brebas doing so. So you need to choose: Brebas or no brebas that is the question !

Option3: do nothing until breba harvest, next year. And act then after the harvest.

They both seem healthy to me and, as long as they're both healthy, I wouldn't worry about the difference in the growth rates and I'd prune them to your liking.  Different cuttings, even from the same tree, can experience different growth rates depending on where on the tree the cutting was taken and a number of other factors. 

I would use any brand of fish fertilizer. I took this tip from another forum member. I noticed huge difference in growth in two weeks time. Noticed new growth in one week. Also helped my satsumas too. Richie from louisiana

The one on the right just started growing figs.  If I remove them it will probably grow faster, but I'm curious for 6 month figs :)

Hello,

Yes, if you prune the smaller branch then it is likely the remaining branch will grow stronger than if not.

Whether you should prune it or not depends on if and how you want to try to shape your tree.

I had the same situation last season on two plants. One plant I left alone and the other I pruned and the difference was obvious. The two branch tree probably had a little more growth if you added the length of the two branches together but the single trunk tree was taller and thicker. Both of them are good!