Don't feel bad about not being able to pick those Schlages. I pick all kinds of other locks with relative ease but I can't ever get those dang Schlages to pick over for me. I bump them open about 90% of the time nowadays, but it wasn't always so easy, I had a few nightmare drill jobs when I first started in this line of work. Lots of sweat and broken drill bits...a little blood, customers telling me the last locksmith picked it open in two minutes. I have been to your same rodeo and I'm pretty sure I rode the same bull as you.
When you do have to drill them, go slow, use lube and sharp drill bits, don't forget to go slow. Take the bit out of the hole often and clean off all the metal shavings. Oh yeah, and location, location, location ! Drilling in the right spot is a beautiful thing. I saw that some of the other guys were saying you should use a plug into the wall type drill, and I'm sure they are more knowledgable than me, but I have never used one to drill a residential schlage, and have no idea why you would need one. Any halfway descent 18 volt cordless should do the job easily if you use it properly.