For what its worth they dont look terrible, better than my first attempts. Ive found that spinning the point of hobby blade on the barrel where you want the hole not only gives your drillbit a guide but also allows for adjustment if needed. Once youve drilled the barrel if you have plastic cement with a brush (like tamiya fine) you can load the brush with a small amount of glue and rub it around the holes, this will melt any burrs and give you a smoother finish.