- Will the dough stick more to the peel with a higher hydration ? (I suppose so)
- Will the dough tear more easily when stretching ? (I think it's something I have read somewhere..)
I've regularly done doughs in the 64-67% range, you don't really have much to fear. Some flour on your work area when opening up the dough will have the surface where you need it, in fact I'd say be more careful about over-flouring. If the dough is tacky and wet you haven't floured enough, if it's sitting in a mountain of flour and your crust has that white floury residue when you finish baking then you way over-floured. I've never had problems working with it, I bring it up to room temp for maybe 1.5 hours before stretching and I hand toss them. Sure, they're more prone to ripping or tearing than a lower percentage dough if you're rough with it, but if you're gentle with it and it had time to build that gluten structure then you really don't have much to worry about - you can still get it very thin and uniform. I'd say you start running into real difficulties with handling at 68%+ but even there it's usually not something you couldn't solve by opening the dough up with a decent amount of flour on your bench.
If you're nervous that the pizza will stick to your peel and be difficult to launch, you could always do what some posters here do and open it up on a strip of parchment paper, put it in the oven on the parchment and then after a couple of minutes of baking, slide the parchment out from under the cooking pizza so it finishes resting on the steel or stone. I've read several people here who do this in lieu of a pizza peel with great results, and there's no worrying about how well a wet/tacky dough will transfer from a peel to the oven. If you have a peel it makes it even easier - build the pizza on parchment
on your peel, then slide the pizza/parchment into the oven - that way you don't have to attempt to carry parchment and uncooked dough to the oven with it drooping/disforming, etc.
Also, as a basic precaution I'd echo what Yael and wotavidone mentioned and make sure your flour is high gluten (high protein) flour. The higher it is, the better gluten structure it will form, the more extensible it will be at any hydration. A low gluten/protein flour with high hydration might have a hard time holding itself together.