Just speculating, but another way to do what Bestetti is doing, is, as @ntempleman
suggested, simply to make that bridging leather a separate piece. Punch the eyes and trim as usual, then add the bridging piece and sew with white (or contrasting) thread using a round point needle (so as not to cut existing threads) right into the same holes as the closing stitches.
Last and bottom the shoes.
When the shoe is done, the white threads would be carefully picked and the whole bridging piece simply slid out. (Again, the bridging piece doesn't have to extend all the way to the bottom of the facings.)
In fact, this might be the only way it could be done with Derbys.
Just a thought...