I'll suggest using a design table with each configuration having unique value for the custom property that will be the indicated text.
You can also use Excel formulas (in columns outboard of the DT's region to compute the text based on an sequential index number.
I replied awhile back on something similar to this with an attached part & DT.
I will have to rummage the forum to see if I can find a link for you.
EDIT: Go here:
I misinterpreted the original post's issue, so my blather didn't apply there, but I think it may help with your issue.
EDIT II: By "outboard", I mean a blank column in the DT on the right so you can do some Excel logic to get your text and then in the DT region, link the property's cell to the computed text cell of the same row.
An alternative is to NOT model the differing text at all and shift this to either the CAM software or the CNC Controller. Your SoldWorks model and / drawing would show an example text and call out size, font, location, and other specifics. But many CAM software packages provide a means for incrementing alpha numerics. And if your CAM software does not, then most CNC controllers have an incrementing function.