Interesting observation Tom. What seems routine to me could be a mystery to someone new to the craft.
Always, when you are planning a build, make drawings, and blue print type plans - full scale. Then you will see the relationships that will shape your rifle. This has been discussed and outlined before on this site, but to re-cap, I start with a sheet of what here is called "Bristol Board"...a white sheet of heavy card stock. Sometimes I join several lengthwise, if I want to draw the entire gun, but usually, I just draw out the butt stock forward until the rifle runs off the paper on the right. I draw the barrel in profile with its breech plug. Then I lay the lock plate over the barrel drawing so that the pan is correctly oriented with the location of the vent. Now I can start drawing in the profile of the wood, starting at the breech along the wrist and comb. The drop I need at the comb and heel is marked on the paper, and lines are joined. I can also now draw in the bottom line of the stock. Here's where the details I listed in my previous post come in. And so forth...