We have always done renovation projects ourselves and are currently doing a complete update of a 1975 home. The issue we can't figure out is in the living room. There is a sheetrock beam at peak of vaulted ceiling that is 24' long. We want to wrap it with wood but have discovered it is inconsistent in every way possible... it sags in the middle (can't visually see it), the height varies, etc. With being so long we can't build it first and install. But if we do it piece by piece on the beam nothing matches up b/c it isn't straight and equal across the beam. How do we do this??? We currently have 4x8 sheets of birch we were intending to cut and nail. Any suggestions would be so appreciated b/c we have brainstormed for weeks and searched all across the web and no ideas. Thanks!