I know a NJ cheesemaker that makes a fantastic ewe's milk Valençay - a very traditional crottin-type pyramid Goats' semi-lactic cheese from the French Loire valley. His version is excellent and I know you can do this well with ewe's milk.
I would not fear slip skin so much, it's a very wet and soft cheese in its first 10 days or so and skin will get bruised and may even peel a bit here and there when you turn it, but it's not like a Camembert slip skin where under the skin you get this gooey madness that turns into ammonia by the time the heart of the cheese matures.
So first of, yes; it should be quite tart. Remember that you are acidifying the milk for 8-18 hours. It can almost taste like yogurt in some cases.
Secondly, do use Geo because it helps control the surface acidity and give you a hearty strong rind and bloom (which will also protect the cheese from drying out past the second week). Using ash can also help with humidity control and stabilizing acidity.
My regiment (on goat's milk) is to drain 12-18 hours in a mold at room temp. Turn over for another 12-18 hours, then do the salting (and ashing if any) and turn over for another 12 hours of draining. Then turn for another 12 hours so you have completed 48 hours draining and open area in room temp. Now I put it in an aging container (paper towel on the bottom, then eleveting platform and then a net on which it rests). I cover it partially and move it to the cave for cooler draining over the next few days. wipe the box dry morning and evening and replace the paper towel if its soaking. By the time the cheese firms up is drier to the touch it will also be blooming. When it has bloomed all around you want to move it to the refrigerator (probably 5-10 days old). I don't wrap it. Shelf life is long, but remember that after about 21 days it begins getting harder.
