Hard Arkansas stones are the best for finish stoning, without a doubt.
Unfortunately, they're also VERY expensive.
I have had great results with a set of hard ceramic stones, available from Brownells. They cut smoothly and evenly, clean up very well with soap and water--and if you get a bit ham-handed and drop one (and break it), they're easy to replace. I have used the same set now for a long, LONG time.
Armchair Bronco, tuning up a gun is actually easy. Simply inspect ALL metal-to-metal rub areas. The only ones you should NOT touch are the ones already listed. Some areas that are usually overlooked are: the mainspring strut and.or retainer; hammer and trigger pivot pins, hammer and trigger travel areas.
Here's a tip: One of the secrets of a good action job is to actually clean up the SPRINGS. You can polish the outer surfaces easily on heavy springs--chuck them gently in a VSR drill, cover the outside of the spring with JB compound, put some oil on a big patch or cloth and turn at slow speed for about 10 seconds. Small springs can be done by hand. Leave the tiny ones alone--they'll tun away and you'll never see them again.
Clean the spring well, and put a drop of oil on them before replacing.
Hey, Dragline--wanna do a good trigger tune on that Smith? Polish the bottom and left side of the rebound slide, shim the hammer boss (Ron Power shims), carefully ream the inside tunnel on the crane and install an endshake bearing; then replace your rebound spring with a 14 lb. Wolff spring. Smooth as silk, with a reliable ignition.