First of all, if you're using a factory barrel and chamber, you may be wasting your time- because factory chamber necks are often large enough that neck expansion will be rather excessive once you've thinned the case necks down. Case necks will expand quite a bit upon firing, then need to be sized down a lot during sizing. The net result of all the expansion and sizing reduction is case necks that split after a few firings.
Most neck turning is done for chambers that have rather tight necks- benchrest chambers that are cut to a specific dimension, or custom chambers that tend to be cut tighter than factory chambers.
If it's a benchrest chamber, the benchrest gunsmith will furnish a dimension that the loaded cartridge case neck must be. Often a benchrest barrel will be stamped '.262 neck', or something like that.
For a chamber that isn't a benchrest chamber, you generally cut the minimum amount off the case neck possible- just enough to cut the brass all the way around the neck. It's a cut and try procedure- you set the neck turning tool to just barely cut, and see if that cuts on all your case necks. If it doesn't, you set the cutter a hair deeper and try again.
As to what tool to use, the first step is get a Sinclair catalog, or go to their website
www.sinclairintl.com. They're a great source for all the benchrest loading equipment.
I use one of their neck turners, the NT-3000 model. Wilson makes a good tool, too, and the new Forster hand tool looks decent, too. Sinclair carries all of them.