Hi, I'm back from the woods, and my 1mm endmill served me well for both small and big holes. I guess my conclusion here is that endmills are OK on small boards where the amounts of small and big holes are fifty-fifty, but if I've got a board with a hundred small holes and two big ones I should use a drill and do a tool change.
Thanks guys, I learnt alot. NOW I'm boring.
Knut