I love running the housings along the front of the tops,just far enough down that they lie under my second knuckle. Feels totally natural and better than simple round.
I reserve holes in the handlebars to outboard of the brake levers. (So far, I have never had a reason to add any out there. Maybe I went to bar end shifters.) I've broken (old and tired) bars at the edge of the stem butting. Drilling holes to speed the failure? Nah.
I consider everything in a line from the road under my front tire to my hands (front wheel, fork, steerer, headtube, stem and handlebars) something close to sacred. I know from first hand experience that failures in that line can be life and death.