Looking over my springs, I have the two short and thin H springs. I have 10 F springs. No single G spring.
The assembly instructions say that F can be used in place of G.
Should I cut spring F down to make it appropriate for replacing G or use it as is (there's more tension with F uncut)?
I've been using F on all my later models with no problems at all. The servo may go off axis by the shoulder alone, but later on it will be constrained by the corners of y1 and y2.
The single screw D just prevents the spring F from jumping out of the location. It won't experience the direct elastic force from the spring.
Just use as is. The design principle prefers universal parts to reduce complexity and confusion.