Originally Posted by
oneclick
Looks fine - why not use a plain drill bit, you'd get way more than that many holes from a decent one; and if your press has any appreciable amount of runout starting the hole (close to) where you want it will be less bother.
Thank you, oneclick, for evaluating my technique and reassuring me. If I ever make another chainring adapter I will try your suggestion of using a plain drill bit.