I've done all coconut oil bars, with 20% superfat, and salt equivalent to about 80% of the oil weight. I used individual molds (because they set up like concrete in a few hours, and a lot of people have trouble with them crumbling when they cut them). I've heard of useing anywhere from 70% to 100% of the oil's weight.
I've also done a 7% superfat, no palm (olive/coconut/cocoa butter/avocado) bar with a smaller percentage of salt, about 4 oz to the 2 lbs of oils. Those sweat a lot more, but after a few weeks, they're pretty nice. I also used Dead Sea Salt, even though I've read you're not supposed to.

Worked for me!
Both types seem to benefit from a longer cure (like months). Neither is drying even to my middle-aged, usually dry skin. Both have a really nice, creamy lather, but I wouldn't say they're exfoliating. I think the salt melts before it can become scrubby.
I've also done rebatch and added coarse salt to it, a couple of tablespoons of coarse salt per pound of shreds. I think it improves the lather, and I like the sparkly look of it on top of the bars. Like little diamonds!