Can anyone answer this, on a cosworth CV joint there are three parts not including the bearings

The outer body: the groove goes to the outside of the shaft ie: stub axle & diff flange, and I know about lining up the wide and narrow sections so they are opposite each other.

the inner splined part has a groove & a number on it which I also know goes to the outer side of the shaft ie: stub axle & diff flange,

Now this is where it gets hard to explain, when you put the inner splined part into the cage you can spin it both ways does it matter which way?

The cage has a larger aperture to fit the inner splined part into it, so which way round should this face ie: the large aperture facing the inner side of the shaft or facing the stub axle & diff flange sides.

I hope the above makes sense as I have had a few cans