You could try a few different maneuvers to help get comfortable with the stress.
You could just plain rover down the set and ride down the steps. You could try a few firecrackers down it too.
Sometimes I like to ragdoll stairs before trying to ollie them. Just put the board down at the landing, start from the top, run, and jump onto the board at the bottom. You could also grab your board, run from the top, jump down the stairs, and put the board to your feet in the air before landing.
At least after trying a few of these you'll be comfortable seeing the stairs pass under you and know what the impact will feel like. You'll have a better idea of how much speed you'll need as well.
I'm reminded of an interview with Jaws in which he mentioned that he jumps down drops on his feet before he skates down them.