I've used the nitric acid with good results, some have had problems, but using it correctly you should have no trouble. If you don't have any carving, it is a breeze, you can lightly wash it down with baking soda/water mix to halt the action of the acid. Potassium Permangnante can give a nice color, but will fade in time. Water based stains work good, but can also fade in time, but they are nice for shading in areas or getting spots to blend in. Laurel Mountain makes a really nice series of stain that can be applied over each other to achive varied colors, that way you don't have to be stuck with a certain color. I've had good success with Laurel Mountain stock finish also.
Glad to hear you got the trigger in. I've had the same thing happen when using set triggers, stock getting thinner in the wrist/lock area. There are triggers out there with taller striking surfaces, but like I said before, I'm partial to single triggers.