Ok,
I have recommended it before, and I will recommend it again. This little accessory is going to make your life MUCH easier. While the auto disk will work just fine, there may not be the exact disk to raise you up in the small increments you need. This will make your powder measure infinitely adjustable.
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=150005
These are the Calipers that I use. They are about the least expensive that are out there, and are 100% accurate.
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=119623
As for the tumbler, I use a Lyman Turbo 1200. But I use the Frankford Arsenal rotary media separator. This kit has the Frankford tumbler, media separator, media, and polish all in one package. I have heard good things about the Frankford tumblers.
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=616153
Of course, if you are not in a big hurry, you may want to check out Ebay for the tumbler. That's where I got mine at a very good discount, and was like new.
As for the scale, when you are exactly on the number you want, you will see 3 lines. The middle line is the one that you read. They do this, so you can see exactly how close to the number you are. Also, you will notice a little knob that is used to bump the slider over. If you push in on that knob, it will lock the slide in place. I find the scale is a bit easier to use if you leave it locked in. You will not have to worry about bumping the slide when you are weighing a charge. Of course you will not be able to do this when you are setting your powder charge, but once you have it set, you can lock it in place, so you can spot check your charge by dumping it into the tray, and hooking it on the scale.
Hope this helps
Adam