Converting from friction to index shifting

[Derosid]

I have an older DeRosa that I converted to index shifting a few years back with some Ergo-8 levers and cable stops that attach to the shifter bosses. I am now updating to 12-speed Campy SR mechanical and notice that the cable guides supplied with the SR group don’t fit into the hole my downtube cable stops.

The shifting seems a bit harder than I expected, but that could just be due to new mechanisms. But I’m wondering if I should try and use the SR cable ends at the downtube. I could drill out the existing holes to accept the cable guides. Or is there a better option for converting the downtube shifter bosses to cable stops for indexed shifiting?