The Estes instructions show the bottom of the UNITED STATES at 6 1/4" from the rear of the body tube. I did a dry fit and that sets the decal too far forward.
Looking at the Peter Alway's Rockets Of The World, the UNITED STATES is centered on the body tube. The old Centuri instructions also show the decal to be centered.
I made a very light pencil center mark on the body tube just outside the final decal position. Another pencil mark was made at the center of the UNITED STATES decal.
When the decal is being transferred simply set the decal center mark on the body tube center mark.
I did a test soak of the Estes logo decal. I let it sit in the water for 30 seconds and the decal was already coming off the backing while still in the water. I decided to do a 20 second soak of the other decals.
TIP: Notice how the UNITED STATES decals read from either side of the rocket. Again this has to do with how the stencil was painted when the real Nike Smoke sat horizontally in the ground cradle. Estes didn't include the cradle marks left on the main body. You can see them in the Alway drawing in the first picture.