What about adding etched grabs onto the fret that can be glued into the holes on the body? This would eliminate the need for BLMA grabs and you could have them painted with the rest of the fret. All we would need to do is clip and glue.
Except that only one side of the etching is being decorated, so that's a problem. And, nickel-silver strength is comparable to brass, so small parts don't hold up well. We could etch a stainless steel fret of grabs, as what was done for the KV Caboose. Most likely, it will come down to cost and availability of the BLMA grabs.
This is getting loaded with WIN.
How many road names (or base colorings) are you planning? I hope not too many, since I'm going to have to get everyone of them.
The current plan is that they will be released one road/scheme at a time, but we have to see how they sell and how strong the demand is. GTW will be first, probably three car numbers.