I have a new loft conversion, it has green moisture resitant plasterboard in bathroom. i want to fit shower panels bought from bathstore in shower cubicle it has a MDF core with some waterproof coating. Would there be any benefit to installing wedi board on top of the green moisture plasterboard (which has been painted white with crown contract mat) to add extra measure to waterproofing the walls. also will shower panel stick onto top of the wedi board using grab adhesive like fix all or pink grip?