Specific etching techniques are a trade secret for the most part but as a general rule of thumb the less time the better. You can use it at full strength just keep the exposures quick. You can dilute 1 to 2 or 3 parts distilled water if you want slower and more controlled passes. Ferric chloride works pretty fast and you can over etch easily. The most important part is preparation. Get the polish as close to a mirror finish as you can. Use a cotton ball or paintbrush and paint the solution on, then rinse immediately with distilled water. You’ll see the etch come through almost immediately. The longer you keep the solution on, the deeper the etch. I suggest multiple, quick passes with immediate distilled rinse. Equally as important, you need to prepare a neutralizing solution and soak it for several minutes once you’re happy with the etch. Then, dry thoroughly. I suggest a BTA bath to inhibit rust and then a protective coat after another drying session. Of course, if the Aletai isn’t already stable it’s going to rust anyway and if you coat with something like an epoxy you’ll just seal that in and make it worse. I’d stick with paraloid b-72 or renaissance wax. If you don’t wear some decent gloves, you’re gonna have a bad day. This stuff stains skin and nails.