I use a common hardware-store countersink bit, held in my fingers, to deburr. A few twists and you're done. I have one of those speed-handle tools from the airplane catalogs, but prefer the countersink. The angle of the c'sink isn't critical for this purpose.
I wouldn't mess with deburring the insides of the holes in tubes, unless you can reach them with a flat file from the end of the tube. Poking around with a rat-tail from outside will probably do more harm than good.