Setting the seam from the back, then pressing it to one side from the front accomplishes two things that I've experienced: 1) It seems to "nestle" the thread into the layers of fabrics, and 2) The seam is now warmed and very pliable to send that seam to one side or the other when ironing from the right side . . . no overlaps or little tucks at the seam.
You'll find that your measurements stay very true as well.
Hope this helps.