Many swear BY AF, and many swear AT it. I would also suggest getting a bottle of Ferric Nitrate crystals to experiment with. A $15 bottle of it from the Science Company will last you a lifetime. They can be dissolved in water or alcohol, but by using water it takes longer for it to evaporate so it gives better penetration. You can more easily control the concentration too. Most guys use a concentration between 4:1 and 6:1. It's essentially the same stuff as AF. But by using the crystals, you'll know exactly what you're putting on there concentration wise, so you can duplicate it more easily.
Another thing to experiment with is your neutralizing agent. Most guys use either household ammonia, or baking soda these days, but back in the day, lye was extremely common. What you use as a neutralizer isn't talked about a lot these days as part of the finishing process, but it IS a part of it.
With this last gun I was pulling my (now rather sparse remaining) hair out after about 20 different concoctions of AF, FN, dye, stain, paint, yadda yadda ---until I read about using lye as a neutralizer. So I decided to try it on one of my test strips (scrap wood from the fore end). I just used a really strong solution of the hardware store stuff (too lazy to boil down wood ash to get it), and it really made a difference in getting the lighter parts of the stripes to jump (thus contrasting with the darker parts) and imbued in a bit of an orangish hue, which was what I was after as well.
After that, (and the lye residue dust being removed) and the over-wash with the next stain was on there, I could rub it all back with steel wool to highlight it further, as the danger of oxidizing the steel wool shards in to black flecks was now (largely) passed, Fred's cautionary note above not withstanding.
A cautionary note about lye though; protect yourself in handling it. In high concentrations it can be every bit as caustic and dangerous to use as concentrated acid, especially around your eyes. If you let it dry on the stock you will get a dusty residue too. That can be brushed off, or, you can just hose down the stock (or take it in to the shower with you to accomplish the same thing while wearing your rubber gloves) shortly after it's on there and has a chance to work.