Totti. I would be really glad to hear what you changed from and to what you did to improve. Only works with wood peel for myself..
For me, this came down to a combination of:
1. Making sure dough is properly leavened. For this last time this actually meant keeping it near the oven for a couple of hours in the dough box.
2. When you cut then balls out of the box, make sure you don't split the edges and use plenty of flour in lifting and separating the balls
3. Drop and begin opening balls on a mound of flour. Don't worry about putting too much on because:
4. When you slap your dough for the final phase of stretching all the excess flour will fly away. Slap away from flour on a clean surface
5. Throw a small amount of flour on the base of the peel. Use too much and your pizza will have a black base and taste very bitter
6. Top pizza and stretch onto peel. Give it a little jiggle and launch. The longer you take to get the pie off the peel the greater chance you have of the heat from the oven making it stick.
Try using more flour on the peel until you get the hang of it. You might be better off with the perforated one with the holes in the bottom. I have a GI metals one on order.