Take a look at these pictures of Euphorbia bupleurifolia and hybrids for more examples of pineapple-looking plants. I am partial to the leafy tuberculate Euphorbias myself.
The mix which I use is 50% pumice, 50% organic (half cocofiber, half compost). You should be able to make an all-inorganic mix work if you increase the watering accordingly.
Was the plant really buried up to the brown line before? Maybe it was seated right in the soil and there was top dressing (coarse rock on top of the soil) up to the line? I would put it up so the minimum amount of actual stem is buried. You can use top dressing to help keep it upright if you need to.
I don't think there is any advantage to waiting more than a week to water.
