Yup, got everything from Brownells. I would highly recommend getting the pilot kit. It comes with a bunch of different sizes so you can find the best fit for each hole, and they most likely will be all a little different.
If your pilot is snug then it's hard to mess up. Just be very generous with the drill-do and give it steady pressure.
I will say the T-handle I bought didn't work. That's why I have that chuck. I didn't mount it to a drill, I just used my hands but the chuck held the bit tight.
I made a few videos when I did my Vaquero
You know you can't own just one .45 revolver. If you ream two then it's paid for itself. You also get the satisfaction of learning a new skill and remember no one treats your stuff as good as you do.