Once you have your morph as deltas - this is what applying the morph and saving the CR2 does, there are several options open to you.

Keeping it as a separate CR2 is almost the least efficient way - (keeping it as a PZ3 in the character library - with all that unnecessary camera/light crap is worse).

What you probably want to do is have your character morph be just like the other V3 morphs - available as an injected morph.
DAZ has provided some additional channels for you to use for this - the potential problem with using them for this is that other 3rd party authors will also use them and there may be a traffic jam.
You do not need to use the readScript function for this, you are not likely to need to call your character face from more than one pose file, so a direct MIpose is good enough.

Copy/Paste the following as a file named: HeadSlot.fc2

{

version
{
number 4.01
}
actor head:1
{
channels
{
}
}
}

Open this file and the CR2 with your morph in MM4
(life will be easier for you if the cr2 you apply your morph into is the V3 BLANK cr2 - much smaller)
(MM4 defaults for CR2, but will open FC2/PZ2 if you ask it to.)

copy your morph over to the HeadSlot.fc2
Save this as WHATEVERYOURCHARACTERNAMEIS.fc2

You now have an MI pose that goes into the face/expression library.

You are not done though - for an MIpose to work, the channel name in the pose must match one in your target CR2.

V3 comes with a lot of extra channels for you to use:
targetGeom PBMCC_01
thru
targetGeom PBMCC_50

Open your new *.fc2 in a text editor and change your morph's channel name from

targetGeom YOURNAME
to
targetGeom PBMCC_01

You leave everything else alone - the name in

name YOURNAME is what shows on the dial and it can stay as the character name.

Now I will probably add (paste in):

targetGeom Faces_V3
{
hidden 1
}

to the V3 base file I work from and have character faces use it, instead of one of the 50 DAZ ones - because I will work from the BLANK and use this method to get character bodies as well as faces into the file.

Anyway - if you eventually have 300 character face morphs,
each can have the same targetGeom ____ in their separate *.fc2 MIpose, because you can only use one character at a time.
The same more or less goes for spawning a morph for each group to define a body shape.

As I said, you can do this with the readScript, but you do not need to. That is used because it allows NoseBig to be called from several different pose files and the actual deltas be gotten from a central location. If you did it directly, the deltas would have to be in each of those pose files and V3 would take up four times more HD space.