I personally look at draw length in a 2 part perspective.
1. The frt half is the bow arm
2. The back half is the draw arm and proper shoulder alignment
I draw the bow with a straight bow arm / rotational and once at full draw slightly unlock it, normal anchors or stopping place for the string should be be near the corner of the eye socket to corner of the mouth which are in a vertical line. This allows the arrow to be placed under the eye.
Once the frt half is set I slowly engage the draw arm back muscles which will pull the draw arm closer to the spine and rotate the elbow in line with the arrow.
If you are over bowed you will never get the rearward alignment correct due to compressed back muscles on the spine which can cost up alot of draw length and in my findings could be upwards of 1,1.5 inches . Strong shoulders make a huge difference.
A rotational draw helps set the rear section of the draw arm/ shoulder but I always take a second to feel where all is settled.
Start will a low weight bow and you will see the difference and build strength from there.