If you are investing on a good anamorphic lens, there is little chance that you would want to change it in x years, unlike a projector. With that in mind, your curved screen may not go wasted or need any change, since you will curve your screen to offset the amount of curvature created by lens. More or less even you change a projector (assuming that you would go with almost same throw distance etc.) and keep the lens, your curved screen will be useful for many years.
I have a optoma H80 and a DIY curved screen. My screen is really a big one - 15 feet wide. The height of the screen is little larger than it should be for a 2.35 aspect ratio. Since I have build a bigger (curved) screen, I am free to mask it in anyway to suit my projection. In my case actual projection is not 15 feet, but about 14.25 Feet. So I mask it both side , right and left and top and bottom with black 'Felt' cloth. Masking it will give you a real theater experience anyway.