Dimples in gib strips

I have a Portass PD5 lathe that I bought used. I am in the process of checking it over and fixing anything that needs fixing. As part of this I have had to make new gib strips for the cross slide and for the saddle. Now I come to make the dimples to locate the strip on the tips of the grub screws. How should these be made? I have seen suggestions that they are often made just with an ordinary drill. If I do this do I drill them with the strip flat or with it held at an angle of 30 degrees? Or do I use a countersink bit? Or do I need to use an end-mill so that the bottom of the hole is flat? The old grub screws seem to have conical tips, but I will probably replace these anyway. Should they be replaced with conical tips or (as I have seen suggested somewhere) cup tips with a small ball bearing brazed into the cup?

Any suggestions on how to do this correctly would be most welcome.

Thank you - Rowan