Thanks for your observations, guys. The instructions that come with the kit will be much more detailed. This is just an introduction to the product, so we didn't want to write a book.
The 2 setscrews are: short for round butt grip frame, long for square butt grip frame. The full directions will tell you to clean the threaded hole and setscrew with acetone, brake parts cleaner, etc.. Wait for solvent to evaporate. Apply Loctite to both internal and external threads and screw in the setscrew. Clean off excess with a cloth or Q-tip. This is low strength Loctite that allows you to make adjustments at any time after it cures, but will hold the screw where you set it. No heat is required to move the screw. You may want to make a small access hole in the grip to allow for easy adjustments on the range.
There will be other instructions as well. For instance, the top hole in the hammer is used to hook a trigger pull gage in for measuring mainspring tension. Once you get the strain screw where you want it, you can record that number for future reference. If you have to take out the mainspring to work on the gun, or replace it, you can dial the mainspring back to where it was before, without shooting a bunch of ammo to find that same spot.
There will be a card with the kit to record when the parts were installed, what gun they are in, (mainly to keep the original parts and gun together), a baggie to put the original parts in, and other information you will want to keep for later. You can see what this looks like by going to the home page, click on support and FAQ, and click on record card.
This is a system, not just a part. While it may seem a bit complex to begin with, once you see how it works, it's all very simple. It takes a lot of explaining because everything is new and different. Once you do one gun, it becomes clear.