I make stretch tutus all the time, but i have only done a back opening for one girl. the problem we had was the hips were considerably larger than the waist, and she couldn't pull it on. I made the bodice opening the same way I make a boned one, i used hook and eye tape to stabilise it, with a placket underneath, so no gaps on show. If possible i sew the plate onto the leotard before i stitch the skirt, but if I cant, i hand stitch it to the top layer of the skirt as close to the bodice as possible, but i make the waist opening just slightly bigger than the finished measurement.
if you pleat the net for the first layer or two, which i always do, make the finished measurement about 1" larger than the hip measurement, then I stitch and gather it up to match the hip measurement before i attach to the leotard.
I always find the decoration of the tutu the hardest thing, so any suggestions on that would be great.