It's only reasonable that multihull boats pay more for berthage than similar length monohulls. It's simple. Larger boats should pay more than smaller boats. Don't expect smaller boats to subsidize larger boats.
But what about draught? What if marinas and the channels serving them have to be regularly dredged to suit the deep keelers? Should the shallow draught boats be subsidising the dredging to suit the deep draught boats?
What do you want? For us to make the phone calls and find the rates where you are located? If you gave a location maybe it would make it easier, or maybe google the marinas in the location you are looking and contact them. Seems the people on this forum have been kind enough to give you a broad idea, now it's up to you.
I was not interested in rates nor any specific locations. My wife asked me if you pay for 2 slips if you have a cat and I told her since I did not know I would ask here. I have to admit I am surprised to learn in most marinas you do not have to.