Campy Brake question

[hollowgram5]

Random question for the Campy folks here on the forum. I've got a set of 9s Record era Dual pivot calipers (f/r) that I'd like to use on my upcoming build. They use pads like these.

My hangup is that I also have a a set of carbon wheels I'd really like to use on this bike, but I don't know that anyone produces a modern insert for the older style holders.

I have fiddled and swapped the post/nut/hardware off of them and onto some shimano-style holders that also have the curved back like the campy holders, and I looked at using my Dual/Single pivot Athena brakes, but they don't really have adequate tire clearance.

Has anyone had good success using a different style holder in the wider slots of these old brakes?

Thanks in advance!