15 mm is a decent shot at it - but it's still a risky project. one or two holes, might pull that off.
100 holes? the probability of disaster increases . . .
someone mentioned above - it would be really smart to use some cheap wood and perfect your technique before starting in the finished project piece. and in the process of that, I'd recommend you increase the forces involved to the point that you do break out both a cross grain and a long grain wall. sounds perhaps silly - but if you actually bust it up in a prototype you'll acquire some experience in 'how much is too much' - you don't want to learn how much is too much on the 73rd hole . . .