If the carburetor body is distorted more than say 0.010", I would try filing away the high points (that is, the screw tabs) without filing the sealing surface, so that the tabs just barely bottom against the matching part when the gasket is compressed the right amount. The tabs have bent because there was originally clearance between them and the matching part, and some heavy-handed person over-tightened the screws, thus bending the tabs down. In other words, soft sealant to fill gaps of less than 0.010", and careful filing to fix bigger problems. Never bend castings, it often results in fractures.
