I would like to tune my 1911 extractors, as the need arises.  I am aware of the Kuhnhausen books.  What tools do you recommend - dremel tool, stones,or both?  Looking for insights here.  Thanks!

Multi-Tool

AGI video series, 4 parts, on the 1911.
Entire section detailing the areas to polish, radius and tweak for best performance. Be prepared to replace parts that get broken or misadjusted while you learn.

Nothing on the 1911 is plug-n-play. Small diamond file, polishing stones and fixtures will quickly add up...if its an occasional thing, best left to the skilled craftsman.

Go to the Brazos Custom web page, Bob Londrigan has a bunch of great articles on keeping guns running like a sewing machine, including one on extractor set-up.  Great stuff.

http://www.blindhogg.com/gunsmith/extractor.html

As far as Tensionioning. I got the gauge set up and it doesn't work .

What I do is take the slide off the gun. Use a loaded round or dummy. ( Weight of the round is important). Place round under extractor with the base lined up in the "Circle" on the breach face..
Round should droop 30 degrees nose down when the slide is held horizontally and it should still retain the round when you give it a light shake.
I like it more on the too little side than the too tight side.

In before "Glock"

Oh, and never Dremel a firearm.  No, really, never Dremel a firearm.

"There are very few gun issues which cannot be exacerbated with the proper application of a rotary tool."

I would recommend a fine cut square needle file to put the necessary bevel on the bottom and hook of the extractor.   I have gotten by without the tension gauge and I don't see it being 100% necessary.

You can wrap 600 grit paper around your needle file to polish any filing marks out.  Any filing grooves you might leave are potential starting points for stress risers, which can result in the hook cracking off at some point .

A good quality set of jewelers or needle files. But no more than than that for fiels in fact, these files are the only sizes you can use on this small of a part.All you need do with a file and just lightly is break an edge or bevel. Polish only with 600 grit and above, never try it with a file. A dremel can have it's application but only as a final polish.
For tension I learned without tools, bend, check, bend, check, it's a laborious and time consuming process, while you learn. I ended up always being conservative with tension trying to get just enough, and having problems. Once I went a little past "enough", was when I got better reliability and function.