It will still work with Nubian milk at 4.6. Mixed breeds or others, it tends to be too grainy if you let it acidify that much. It's hard to say, you have to see what the curd is doing and adjust the recipe.
With goat milk, you have to play around a bit with the drain pH/mill pH balance to make sure that when you fuse the curds together, they are still curds, and not like a lactic style chevre frais. Draining is different, too, because cow milk curd will find an equilibrium based mostly on the floc, rennet amount, and cook schedule. Goat milk curd lets go of moisture a tad faster.
It shouldn't be dry. It should be fairly moist (that's why we add in cream, to help with the creaminess). But if dry, it will still come together, and you can still smooth out the sides. It does compact some.
Check weight. If your yield is low, might be a mismatch for rennet and your milk type, or something else is off.